<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, sans-serif;
      color: #1e2945;
      background: transparent;
      padding: 16px 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100%;
    }

    .nav-tabs {
      display: flex;
      gap: 8px;
      margin-bottom: 20px;
      background: #f1f5f9;
      padding: 4px;
      border-radius: 999px;
    }

    .tab-btn {
      border: none;
      background: transparent;
      padding: 6px 14px;
      border-radius: 999px;
      font-size: 13px;
      font-weight: 600;
      color: #64748b;
      cursor: pointer;
      transition: all 0.25s ease;
    }

    .tab-btn.active {
      background: #ffffff;
      color: #0f172a;
      box-shadow: 0 1px 3px rgba(0,0,0,0.1);
    }

    .timeline-container {
      position: relative;
      width: 100%;
      max-width: 500px;
      display: flex;
      flex-direction: column;
      gap: 16px;
    }

    /* Main visual track */
    .track-wrapper {
      position: relative;
      display: grid;
      grid-template-columns: 1fr auto 1fr;
      align-items: center;
      gap: 8px;
      padding: 10px 0;
    }

    /* Anchor Center */
    .present-node {
      display: flex;
      flex-direction: column;
      align-items: center;
      z-index: 2;
    }

    .present-badge {
      background: #0f172a;
      color: #ffffff;
      padding: 6px 10px;
      border-radius: 6px;
      font-size: 12px;
      font-weight: 700;
      letter-spacing: 0.5px;
      text-transform: uppercase;
      white-space: nowrap;
    }

    .present-pin {
      width: 2px;
      height: 14px;
      background: #0f172a;
      margin: 2px 0;
    }

    .present-dot {
      width: 10px;
      height: 10px;
      background: #0f172a;
      border-radius: 50%;
      box-shadow: 0 0 0 3px #e2e8f0;
    }

    /* Arms / Arrows */
    .arm {
      position: relative;
      display: flex;
      flex-direction: column;
      border-radius: 12px;
      padding: 12px 10px;
      transition: opacity 0.3s ease, transform 0.3s ease;
      cursor: pointer;
    }

    .arm.dimmed {
      opacity: 0.25;
      transform: scale(0.97);
    }

    /* Teal Retrospective */
    .arm-retro {
      background: #f0fdfa;
      border: 1.5px solid #0d9488;
      text-align: right;
      align-items: flex-end;
    }

    /* Indigo Prospective */
    .arm-pro {
      background: #eef2ff;
      border: 1.5px solid #4f46e5;
      text-align: left;
      align-items: flex-start;
    }

    .arm-header {
      display: flex;
      align-items: center;
      gap: 6px;
      font-size: 14px;
      font-weight: 700;
    }

    .arm-retro .arm-header { color: #0f766e; }
    .arm-pro .arm-header { color: #4338ca; }

    .arm-arrow {
      font-size: 16px;
      line-height: 1;
    }

    .arm-desc {
      font-size: 12px;
      font-weight: 500;
      margin-top: 4px;
      color: #475569;
    }

    /* Direction Bar Graphic */
    .time-bar {
      position: relative;
      height: 6px;
      width: 100%;
      border-radius: 3px;
      margin-top: 8px;
    }

    .bar-retro {
      background: linear-gradient(to left, #0d9488, #99f6e4);
    }

    .bar-pro {
      background: linear-gradient(to right, #4f46e5, #c7d2fe);
    }

    .study-label {
      font-size: 11px;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      opacity: 0.8;
    }

    .sub-tag {
      font-size: 10px;
      font-weight: 600;
      padding: 2px 6px;
      border-radius: 4px;
      margin-top: 6px;
      display: inline-block;
    }

    .tag-retro { background: #ccfbf1; color: #115e59; }
    .tag-pro { background: #e0e7ff; color: #3730a3; }
  </style>
</head>
<body>

  <div class="nav-tabs" role="tablist">
    <button class="tab-btn active" id="btn-all" onclick="setView('all')">Compare Both</button>
    <button class="tab-btn" id="btn-retro" onclick="setView('retro')">Retrospective</button>
    <button class="tab-btn" id="btn-pro" onclick="setView('pro')">Prospective</button>
  </div>

  <div class="timeline-container">
    <div class="track-wrapper">
      
      
      <div class="arm arm-retro" id="arm-retro" onclick="setView('retro')">
        <span class="study-label" style="color: #0f766e;">Past</span>
        <div class="arm-header">
          <span class="arm-arrow">◀</span>
          <span>Retrospective</span>
        </div>
        <div class="time-bar bar-retro"></div>
        <span class="sub-tag tag-retro">Past records & history</span>
      </div>

      
      <div class="present-node">
        <div class="present-badge">Present</div>
        <div class="present-pin"></div>
        <div class="present-dot"></div>
        <span style="font-size: 10px; font-weight: 600; color: #64748b; margin-top: 4px; white-space: nowrap;">Study Starts</span>
      </div>

      
      <div class="arm arm-pro" id="arm-pro" onclick="setView('pro')">
        <span class="study-label" style="color: #4338ca;">Future</span>
        <div class="arm-header">
          <span>Prospective</span>
          <span class="arm-arrow">▶</span>
        </div>
        <div class="time-bar bar-pro"></div>
        <span class="sub-tag tag-pro">Track future outcomes</span>
      </div>

    </div>
  </div>

  <script>
    function setView(mode) {
      const retro = document.getElementById('arm-retro');
      const pro = document.getElementById('arm-pro');
      const btnAll = document.getElementById('btn-all');
      const btnRetro = document.getElementById('btn-retro');
      const btnPro = document.getElementById('btn-pro');

      [btnAll, btnRetro, btnPro].forEach(b => b.classList.remove('active'));

      if (mode === 'retro') {
        btnRetro.classList.add('active');
        retro.classList.remove('dimmed');
        pro.classList.add('dimmed');
      } else if (mode === 'pro') {
        btnPro.classList.add('active');
        pro.classList.remove('dimmed');
        retro.classList.add('dimmed');
      } else {
        btnAll.classList.add('active');
        retro.classList.remove('dimmed');
        pro.classList.remove('dimmed');
      }
    }
  </script>
</body>
</html>

Classifying Statistical Studies: Surveys, Observational Studies, and Experiments

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="1:1">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #ffffff;
      color: #1e2945;
      padding: 10px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100%;
    }

    .container {
      width: 100%;
      max-width: 540px;
      display: flex;
      flex-direction: column;
      gap: 8px;
    }

    /* Top Column Header */
    .col-header-bar {
      display: grid;
      grid-template-columns: 80px 1fr 1fr;
      gap: 6px;
      align-items: end;
      text-align: center;
    }
    .axis-title {
      font-size: 11px;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      color: #64748b;
      line-height: 1.2;
    }
    .col-axis-label {
      grid-column: 2 / span 2;
      padding-bottom: 2px;
      color: #0284c7;
    }
    .col-btn {
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      border-radius: 6px;
      padding: 4px 2px;
      font-size: 12px;
      font-weight: 700;
      color: #334155;
    }

    /* Grid Body */
    .grid-container {
      display: grid;
      grid-template-columns: 80px 1fr 1fr;
      grid-template-rows: 1fr 1fr;
      gap: 6px;
    }

    /* Row Headers */
    .row-header {
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      text-align: center;
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 6px;
      padding: 4px;
      gap: 2px;
    }
    .row-val {
      font-size: 12px;
      font-weight: 700;
      color: #334155;
    }
    .row-axis-tag {
      font-size: 9px;
      font-weight: 700;
      text-transform: uppercase;
      color: #64748b;
      line-height: 1.1;
    }

    /* Inference Cells */
    .cell {
      border-radius: 8px;
      padding: 8px 6px;
      display: flex;
      flex-direction: column;
      justify-content: space-between;
      gap: 6px;
      cursor: pointer;
      transition: box-shadow 0.2s ease, transform 0.15s ease;
      border: 1.5px solid transparent;
      user-select: none;
    }
    .cell:active {
      transform: scale(0.98);
    }
    .cell.active {
      box-shadow: 0 0 0 3px #0284c7;
    }

    /* Cell Types / Color Schemes */
    .cell-green {
      background: #f0fdf4;
      border-color: #86efac;
    }
    .cell-amber {
      background: #fffbeb;
      border-color: #fde68a;
    }
    .cell-red {
      background: #fef2f2;
      border-color: #fecaca;
    }

    .cell-head {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 4px;
    }
    .cell-title {
      font-size: 11px;
      font-weight: 800;
      letter-spacing: -0.2px;
      line-height: 1.1;
    }
    .cell-green .cell-title { color: #166534; }
    .cell-amber .cell-title { color: #92400e; }
    .cell-red .cell-title { color: #991b1b; }

    .tag-list {
      display: flex;
      flex-direction: column;
      gap: 4px;
    }
    .tag {
      display: flex;
      align-items: center;
      gap: 4px;
      font-size: 11px;
      font-weight: 600;
      line-height: 1.1;
      padding: 3px 5px;
      border-radius: 4px;
      background: rgba(255, 255, 255, 0.85);
    }
    .tag-icon {
      font-size: 11px;
      line-height: 1;
      flex-shrink: 0;
    }
    .tag-yes { color: #15803d; }
    .tag-no { color: #b91c1c; }

    /* Interactive Inspector Footnote */
    .detail-bar {
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      padding: 8px 10px;
      display: flex;
      align-items: center;
      gap: 8px;
      font-size: 12px;
      line-height: 1.3;
      color: #334155;
    }
    .detail-icon {
      font-size: 16px;
      flex-shrink: 0;
    }
    .detail-text strong {
      color: #0f172a;
    }

    @media (max-width: 380px) {
      .col-header-bar, .grid-container {
        grid-template-columns: 68px 1fr 1fr;
        gap: 4px;
      }
      .cell { padding: 6px 4px; gap: 4px; }
      .cell-title { font-size: 10px; }
      .tag { font-size: 10px; padding: 2px 4px; }
      .detail-bar { font-size: 11px; padding: 6px 8px; }
    }
  </style>
</head>
<body>

<div class="container">
  
  <div class="col-header-bar">
    <div></div>
    <div class="axis-title col-axis-label">Randomly Assigned?</div>
  </div>
  <div class="col-header-bar">
    <div class="axis-title" style="color:#6366f1;">Random Selection?</div>
    <div class="col-btn">YES</div>
    <div class="col-btn">NO</div>
  </div>

  
  <div class="grid-container">
    
    <div class="row-header">
      <span class="row-val">YES</span>
      <span class="row-axis-tag">Selected</span>
    </div>

    
    <div class="cell cell-green active" id="cell-yy" onclick="selectCell('yy')">
      <div class="cell-head">
        <span class="cell-title">Ideal Experiment</span>
        <span>✨</span>
      </div>
      <div class="tag-list">
        <div class="tag tag-yes"><span class="tag-icon">✓</span> Causal link</div>
        <div class="tag tag-yes"><span class="tag-icon">✓</span> Generalize all</div>
      </div>
    </div>

    
    <div class="cell cell-amber" id="cell-yn" onclick="selectCell('yn')">
      <div class="cell-head">
        <span class="cell-title">Sample Survey</span>
        <span>📋</span>
      </div>
      <div class="tag-list">
        <div class="tag tag-no"><span class="tag-icon">✕</span> Association only</div>
        <div class="tag tag-yes"><span class="tag-icon">✓</span> Generalize all</div>
      </div>
    </div>

    
    <div class="row-header">
      <span class="row-val">NO</span>
      <span class="row-axis-tag">Selected</span>
    </div>

    
    <div class="cell cell-amber" id="cell-ny" onclick="selectCell('ny')">
      <div class="cell-head">
        <span class="cell-title">Lab Trial</span>
        <span>🧪</span>
      </div>
      <div class="tag-list">
        <div class="tag tag-yes"><span class="tag-icon">✓</span> Causal link</div>
        <div class="tag tag-no"><span class="tag-icon">✕</span> Volunteers only</div>
      </div>
    </div>

    
    <div class="cell cell-red" id="cell-nn" onclick="selectCell('nn')">
      <div class="cell-head">
        <span class="cell-title">Anecdote / Case</span>
        <span>👀</span>
      </div>
      <div class="tag-list">
        <div class="tag tag-no"><span class="tag-icon">✕</span> Association only</div>
        <div class="tag tag-no"><span class="tag-icon">✕</span> Sample only</div>
      </div>
    </div>
  </div>

  
  <div class="detail-bar" id="detail">
    <span class="detail-icon" id="detail-ico">✨</span>
    <span class="detail-text" id="detail-txt">
      <strong>Random assignment</strong> establishes causation. <strong>Random selection</strong> allows generalization.
    </span>
  </div>
</div>

<script>
  const info = {
    yy: {
      ico: '✨',
      txt: '<strong>Ideal Experiment:</strong> Random assignment proves causation; random selection generalizes to the full population.'
    },
    yn: {
      ico: '📋',
      txt: '<strong>Observational Survey:</strong> Generalizes to population, but confounding variables prevent claiming causation.'
    },
    ny: {
      ico: '🧪',
      txt: '<strong>Volunteer Experiment:</strong> Shows cause and effect, but only for individuals similar to study participants.'
    },
    nn: {
      ico: '👀',
      txt: '<strong>Anecdote / Voluntary:</strong> Cannot prove causation nor generalize beyond this specific group.'
    }
  };

  function selectCell(key) {
    document.querySelectorAll('.cell').forEach(c => c.classList.remove('active'));
    const target = document.getElementById('cell-' + key);
    if (target) target.classList.add('active');
    
    document.getElementById('detail-ico').textContent = info[key].ico;
    document.getElementById('detail-txt').innerHTML = info[key].txt;
  }
</script>

</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    }
    html, body {
      width: 100%;
      background: #f8f9fa;
      color: #1e2945;
    }
    .diagram-root {
      width: 100%;
      max-width: 640px;
      margin: 0 auto;
      padding: 12px;
      display: flex;
      flex-direction: column;
      gap: 12px;
    }
    .cards-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 8px;
    }
    .study-card {
      background: #ffffff;
      border: 1.5px solid #e6e6e6;
      border-radius: 10px;
      padding: 10px 6px;
      display: flex;
      flex-direction: column;
      align-items: center;
      text-align: center;
      cursor: pointer;
      user-select: none;
      transition: border-color 0.2s ease, box-shadow 0.2s ease, background-color 0.2s ease;
    }
    .study-card:hover {
      background-color: #f1f5f9;
    }
    .study-card.active {
      border-color: #0284c7;
      background-color: #ffffff;
      box-shadow: 0 0 0 2px rgba(2, 132, 199, 0.25);
    }
    .card-icon {
      font-size: 24px;
      line-height: 1.1;
      margin-bottom: 4px;
    }
    .card-title {
      font-size: 13px;
      font-weight: 700;
      color: #1e2945;
      margin-bottom: 4px;
      line-height: 1.2;
    }
    .badge {
      font-size: 11px;
      font-weight: 700;
      padding: 3px 6px;
      border-radius: 5px;
      margin-top: 2px;
      background: #e2e8f0;
      color: #1e293b;
      line-height: 1.2;
    }
    .badge.highlight {
      background: #dbeafe;
      color: #1e40af;
    }

    /* Detail Stage */
    .focus-stage {
      background: #ffffff;
      border: 1.5px solid #e6e6e6;
      border-radius: 10px;
      padding: 16px 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 12px;
      min-height: 190px;
    }
    .flow-row {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      width: 100%;
    }
    .node {
      background: #f8fafc;
      border: 1.5px solid #cbd5e1;
      border-radius: 8px;
      padding: 8px 10px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 4px;
      min-width: 68px;
    }
    .node-icon {
      font-size: 18px;
      line-height: 1;
    }
    .node-label {
      font-size: 12px;
      font-weight: 700;
      color: #0f172a;
    }
    .arrow-wrapper {
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .arrow {
      font-size: 16px;
      font-weight: 800;
      color: #475569;
    }
    .arrow-right {
      display: inline-block;
    }
    .arrow-down {
      display: none;
    }
    .stage-summary {
      font-size: 13px;
      font-weight: 600;
      color: #1e2945;
      text-align: center;
      line-height: 1.4;
      max-width: 480px;
    }
    .tag-rule {
      display: inline-block;
      font-size: 11px;
      font-weight: 800;
      padding: 4px 10px;
      border-radius: 12px;
      text-transform: uppercase;
      letter-spacing: 0.5px;
    }
    .tag-passive {
      background: #f1f5f9;
      color: #1e293b;
      border: 1px solid #cbd5e1;
    }
    .tag-active {
      background: #fee2e2;
      color: #991b1b;
      border: 1px solid #fca5a5;
    }

    /* Mobile Adaptations */
    @media (max-width: 480px) {
      .cards-grid {
        gap: 6px;
      }
      .study-card {
        padding: 8px 4px;
      }
      .card-icon {
        font-size: 20px;
      }
      .card-title {
        font-size: 11px;
      }
      .badge {
        font-size: 10px;
        padding: 2px 4px;
      }
      .flow-row {
        flex-direction: column;
        gap: 4px;
      }
      .node {
        flex-direction: row;
        justify-content: center;
        width: 100%;
        max-width: 180px;
        padding: 6px 10px;
        gap: 8px;
      }
      .arrow-right {
        display: none;
      }
      .arrow-down {
        display: inline-block;
      }
    }
  </style>
</head>
<body>

  <div class="diagram-root">
    
    <div class="cards-grid">
      <div class="study-card active" id="card-0" onclick="showStudy(0)">
        <div class="card-icon">📋</div>
        <div class="card-title">Sample Survey</div>
        <div class="badge">Asks Questions</div>
      </div>

      <div class="study-card" id="card-1" onclick="showStudy(1)">
        <div class="card-icon">🔍</div>
        <div class="card-title">Observational</div>
        <div class="badge">Tracks Habits</div>
      </div>

      <div class="study-card" id="card-2" onclick="showStudy(2)">
        <div class="card-icon">🧪</div>
        <div class="card-title">Experiment</div>
        <div class="badge highlight">Applies Action</div>
      </div>
    </div>

    
    <div class="focus-stage" id="stage">
      
    </div>
  </div>

  <script>
    const data = [
      {
        nodes: [
          { icon: '👥', label: 'Sample' },
          { icon: '❓', label: 'Questions' },
          { icon: '📊', label: 'Responses' }
        ],
        summary: 'Measures opinions/traits via questions without altering environment',
        tag: 'No Intervention',
        isIntervention: false
      },
      {
        nodes: [
          { icon: '🏃', label: 'Subjects' },
          { icon: '👀', label: 'Observe' },
          { icon: '📝', label: 'Record' }
        ],
        summary: 'Tracks naturally occurring behaviors without intervention',
        tag: 'No Intervention',
        isIntervention: false
      },
      {
        nodes: [
          { icon: '👥', label: 'Subjects' },
          { icon: '🎲', label: 'Randomize' },
          { icon: '💊', label: 'Treatments' },
          { icon: '⚖️', label: 'Compare' }
        ],
        summary: 'Imposes treatments randomly on groups to compare outcomes',
        tag: 'Direct Intervention',
        isIntervention: true
      }
    ];

    function showStudy(index) {
      document.querySelectorAll('.study-card').forEach((card, i) => {
        card.classList.toggle('active', i === index);
      });

      const current = data[index];
      const stage = document.getElementById('stage');

      let flowHtml = '<div class="flow-row">';
      current.nodes.forEach((node, i) => {
        flowHtml += `
          <div class="node">
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          flowHtml += `
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              <span class="arrow arrow-down">↓</span>
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      });
      flowHtml += '</div>';

      const tagClass = current.isIntervention ? 'tag-active' : 'tag-passive';
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        <div class="stage-summary">${current.summary}</div>
        <span class="tag-rule ${tagClass}">${current.tag}</span>
      `;

      stage.innerHTML = flowHtml;
    }

    // Initialize default view
    showStudy(0);
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, sans-serif;
      color: #1e2945;
      background: transparent;
      padding: 12px;
      display: flex;
      flex-direction: column;
      gap: 12px;
      min-height: 100%;
    }

    .header-bar {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 0 4px;
    }

    .title {
      font-size: 15px;
      font-weight: 700;
      letter-spacing: -0.2px;
    }

    .takeaway-pill {
      font-size: 12px;
      font-weight: 700;
      color: #0284c7;
      background: #e0f2fe;
      padding: 4px 10px;
      border-radius: 999px;
    }

    .grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 12px;
      flex: 1;
    }

    @media (max-width: 440px) {
      .grid {
        grid-template-columns: 1fr;
      }
    }

    .panel {
      border-radius: 12px;
      padding: 12px;
      display: flex;
      flex-direction: column;
      justify-content: space-between;
      transition: box-shadow 0.2s ease;
    }

    .panel-biased {
      background: #fef2f2;
      border: 2px solid #fecaca;
    }

    .panel-rep {
      background: #f0fdf4;
      border: 2px solid #bbf7d0;
    }

    .poll-name {
      font-size: 15px;
      font-weight: 800;
      display: flex;
      align-items: center;
      justify-content: space-between;
    }

    .status-badge {
      font-size: 11px;
      font-weight: 700;
      padding: 2px 8px;
      border-radius: 6px;
      text-transform: uppercase;
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    .badge-error {
      background: #ef4444;
      color: #fff;
    }

    .badge-success {
      background: #16a34a;
      color: #fff;
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    .stat-row {
      display: flex;
      align-items: baseline;
      gap: 6px;
      margin: 8px 0;
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    .stat-n {
      font-size: 20px;
      font-weight: 900;
    }

    .stat-desc {
      font-size: 12px;
      color: #64748b;
      font-weight: 600;
    }

    .sample-visual {
      background: #fff;
      border-radius: 8px;
      padding: 8px 10px;
      margin-bottom: 8px;
      border: 1px solid rgba(0,0,0,0.06);
    }

    .sample-icons {
      font-size: 16px;
      margin-bottom: 4px;
      letter-spacing: 2px;
    }

    .sample-tag {
      font-size: 11px;
      font-weight: 700;
    }

    .tag-biased { color: #dc2626; }
    .tag-rep { color: #15803d; }

    .result-box {
      background: #fff;
      border-radius: 8px;
      padding: 8px 10px;
      border: 1px solid rgba(0,0,0,0.06);
    }

    .bar-group {
      margin-bottom: 6px;
    }

    .bar-group:last-child {
      margin-bottom: 0;
    }

    .bar-label {
      display: flex;
      justify-content: space-between;
      font-size: 11px;
      font-weight: 700;
      margin-bottom: 2px;
      color: #475569;
    }

    .bar-track {
      height: 8px;
      background: #e2e8f0;
      border-radius: 4px;
      overflow: hidden;
    }

    .bar-fill {
      height: 100%;
      border-radius: 4px;
    }

    .fill-landon { background: #ef4444; }
    .fill-fdr { background: #16a34a; }
  </style>
</head>
<body>

  <div class="header-bar">
    <div class="title">1936 US Election Polls</div>
    <div class="takeaway-pill">Representation &gt; Size</div>
  </div>

  <div class="grid">
    
    <div class="panel panel-biased">
      <div>
        <div class="poll-name">
          <span>Literary Digest</span>
          <span class="status-badge badge-error">❌ Biased</span>
        </div>
        <div class="stat-row">
          <span class="stat-n">n = 2.3M</span>
          <span class="stat-desc">(Huge)</span>
        </div>
      </div>

      <div class="sample-visual">
        <div class="sample-icons">🚗 📞 💎</div>
        <div class="sample-tag tag-biased">Wealthy lists only</div>
      </div>

      <div class="result-box">
        <div class="bar-group">
          <div class="bar-label">
            <span>Predicted: Landon</span>
            <span>57%</span>
          </div>
          <div class="bar-track">
            <div class="bar-fill fill-landon" style="width: 57%;"></div>
          </div>
        </div>
        <div class="bar-group">
          <div class="bar-label">
            <span>Actual: Roosevelt</span>
            <span>61%</span>
          </div>
          <div class="bar-track">
            <div class="bar-fill fill-fdr" style="width: 61%;"></div>
          </div>
        </div>
      </div>
    </div>

    
    <div class="panel panel-rep">
      <div>
        <div class="poll-name">
          <span>George Gallup</span>
          <span class="status-badge badge-success">✓ Accurate</span>
        </div>
        <div class="stat-row">
          <span class="stat-n">n = 50,000</span>
          <span class="stat-desc">(Small)</span>
        </div>
      </div>

      <div class="sample-visual">
        <div class="sample-icons">👥 🌾 🏭 🏢</div>
        <div class="sample-tag tag-rep">Representative sample</div>
      </div>

      <div class="result-box">
        <div class="bar-group">
          <div class="bar-label">
            <span>Predicted: Roosevelt</span>
            <span>56%</span>
          </div>
          <div class="bar-track">
            <div class="bar-fill fill-fdr" style="width: 56%;"></div>
          </div>
        </div>
        <div class="bar-group">
          <div class="bar-label">
            <span>Actual: Roosevelt</span>
            <span>61%</span>
          </div>
          <div class="bar-track">
            <div class="bar-fill fill-fdr" style="width: 61%;"></div>
          </div>
        </div>
      </div>
    </div>
  </div>

</body>
</html>

Evaluating Sampling Methods in Media Claims

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e2945;
      background: transparent;
      padding: 12px 8px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100%;
    }

    .container {
      width: 100%;
      max-width: 660px;
      display: flex;
      flex-direction: column;
      gap: 14px;
    }

    .topic-header {
      text-align: center;
      font-size: 13px;
      font-weight: 600;
      color: #64748b;
      letter-spacing: 0.04em;
      text-transform: uppercase;
    }

    .columns {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
      gap: 16px;
      position: relative;
    }

    .column {
      border-radius: 12px;
      padding: 16px;
      display: flex;
      flex-direction: column;
      justify-content: space-between;
      gap: 14px;
      transition: box-shadow 0.25s ease;
    }

    /* Left: Emotional framing */
    .col-left {
      background: #fff1f2;
      border: 1px solid #fecdd3;
    }

    /* Right: Cost framing */
    .col-right {
      background: #f0f9ff;
      border: 1px solid #bae6fd;
    }

    .badge {
      display: inline-flex;
      align-items: center;
      gap: 6px;
      font-size: 12px;
      font-weight: 700;
      padding: 4px 10px;
      border-radius: 999px;
      align-self: flex-start;
    }

    .badge-rose {
      background: #ffe4e6;
      color: #9f1239;
    }

    .badge-blue {
      background: #e0f2fe;
      color: #0369a1;
    }

    .prompt-box {
      font-size: 14px;
      line-height: 1.5;
      color: #1e2945;
      font-style: italic;
    }

    mark.red-pill {
      background: #fecdd3;
      color: #9f1239;
      font-weight: 700;
      border-radius: 4px;
      padding: 2px 6px;
      font-style: normal;
    }

    mark.blue-pill {
      background: #bae6fd;
      color: #0369a1;
      font-weight: 700;
      border-radius: 4px;
      padding: 2px 6px;
      font-style: normal;
    }

    .metric-section {
      display: flex;
      flex-direction: column;
      gap: 6px;
    }

    .metric-row {
      display: flex;
      justify-content: space-between;
      align-items: baseline;
    }

    .metric-val {
      font-size: 26px;
      font-weight: 800;
      line-height: 1;
    }

    .val-rose {
      color: #e11d48;
    }

    .val-blue {
      color: #0284c7;
    }

    .metric-label {
      font-size: 12px;
      font-weight: 600;
      color: #64748b;
    }

    .track {
      width: 100%;
      height: 10px;
      background: #e2e8f0;
      border-radius: 999px;
      overflow: hidden;
      position: relative;
    }

    .fill {
      height: 100%;
      border-radius: 999px;
      width: 0%;
      transition: width 0.9s cubic-bezier(0.16, 1, 0.3, 1);
    }

    .fill-rose {
      background: #f43f5e;
    }

    .fill-blue {
      background: #0284c7;
    }

    .annotation {
      font-size: 12px;
      line-height: 1.4;
      color: #475569;
    }

    /* Bottom Delta Callout */
    .delta-container {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 6px;
      position: relative;
      margin-top: 2px;
    }

    .delta-pill {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      background: #f8fafc;
      border: 1px solid #cbd5e1;
      padding: 8px 16px;
      border-radius: 999px;
      font-size: 13px;
      font-weight: 700;
      color: #1e2945;
      box-shadow: 0 1px 3px rgba(0,0,0,0.05);
      text-align: center;
    }

    .delta-tag {
      background: #e11d48;
      color: #ffffff;
      padding: 2px 7px;
      border-radius: 6px;
      font-size: 12px;
      font-weight: 800;
    }

    .interactive-bar {
      display: flex;
      justify-content: center;
      margin-top: 2px;
    }

    .replay-btn {
      background: #ffffff;
      border: 1px solid #cbd5e1;
      color: #475569;
      font-size: 12px;
      font-weight: 600;
      padding: 5px 12px;
      border-radius: 6px;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      transition: background 0.2s, border-color 0.2s;
    }

    .replay-btn:hover {
      background: #f1f5f9;
      border-color: #94a3b8;
    }

    .replay-btn:active {
      background: #e2e8f0;
    }
  </style>
</head>
<body>

  <div class="container">
    <div class="topic-header">Same Policy Topic: Industrial Emissions Regulation</div>

    <div class="columns">
      
      <div class="column col-left">
        <div class="badge badge-rose">⚠️ Emotional Justification</div>

        <p class="prompt-box">
          &ldquo;Given that emissions cause <mark class="red-pill">toxic asthma spikes</mark> in <mark class="red-pill">children</mark>, should factories face stricter limits?&rdquo;
        </p>

        <div class="metric-section">
          <div class="metric-row">
            <span class="metric-val val-rose">84%</span>
            <span class="metric-label">Support Regulation</span>
          </div>
          <div class="track">
            <div class="fill fill-rose" id="barLeft" style="width: 0%;"></div>
          </div>
        </div>

        <p class="annotation">
          Steers respondents by highlighting severe health harms.
        </p>
      </div>

      
      <div class="column col-right">
        <div class="badge badge-blue">⚖️ Tangible Cost Framing</div>

        <p class="prompt-box">
          &ldquo;Do you favor or oppose stricter factory emission limits if it <mark class="blue-pill">increases consumer goods prices</mark>?&rdquo;
        </p>

        <div class="metric-section">
          <div class="metric-row">
            <span class="metric-val val-blue">48%</span>
            <span class="metric-label">Support Regulation</span>
          </div>
          <div class="track">
            <div class="fill fill-blue" id="barRight" style="width: 0%;"></div>
          </div>
        </div>

        <p class="annotation">
          Dampens support by introducing direct financial cost.
        </p>
      </div>
    </div>

    
    <div class="delta-container">
      <div class="delta-pill">
        <span class="delta-tag">Δ 36%</span>
        <span>Framing alone changes public support by 36 percentage points</span>
      </div>
      <div class="interactive-bar">
        <button class="replay-btn" id="replayBtn" type="button">
          ↻ Replay Comparison
        </button>
      </div>
    </div>
  </div>

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    function triggerAnimation() {
      const leftBar = document.getElementById('barLeft');
      const rightBar = document.getElementById('barRight');

      // Reset
      leftBar.style.transition = 'none';
      rightBar.style.transition = 'none';
      leftBar.style.width = '0%';
      rightBar.style.width = '0%';

      // Trigger reflow & animate
      requestAnimationFrame(() => {
        setTimeout(() => {
          leftBar.style.transition = 'width 0.8s cubic-bezier(0.16, 1, 0.3, 1)';
          rightBar.style.transition = 'width 0.8s cubic-bezier(0.16, 1, 0.3, 1)';
          leftBar.style.width = '84%';
          rightBar.style.width = '48%';
        }, 50);
      });
    }

    // Run on initial load
    window.addEventListener('DOMContentLoaded', triggerAnimation);
    document.getElementById('replayBtn').addEventListener('click', triggerAnimation);
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      background: transparent;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
      color: #1e2945;
      padding: 12px;
      display: flex;
      flex-direction: column;
      gap: 10px;
      min-height: 100%;
    }
    .header-row {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 0 4px;
    }
    .headline-pill {
      font-size: 13px;
      font-weight: 700;
      color: #1e2945;
      background: #f1f5f9;
      padding: 4px 10px;
      border-radius: 6px;
      display: inline-flex;
      align-items: center;
      gap: 6px;
    }
    .claim-tag {
      color: #475569;
      font-weight: 600;
    }
    .scorecard {
      display: flex;
      flex-direction: column;
      gap: 8px;
      width: 100%;
    }
    .audit-row {
      display: grid;
      grid-template-columns: 1fr auto;
      align-items: center;
      gap: 12px;
      padding: 10px 14px;
      border-radius: 8px;
      background: #ffffff;
      border: 1.5px solid #e2e8f0;
      opacity: 0.35;
      transition: opacity 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
      cursor: pointer;
    }
    .audit-row.active {
      opacity: 1;
      border-color: #ef4444;
      box-shadow: 0 2px 8px rgba(239, 68, 68, 0.12);
    }
    .audit-row.revealed {
      opacity: 1;
    }
    .row-info {
      display: flex;
      flex-direction: column;
      gap: 3px;
    }
    .row-title {
      font-size: 14px;
      font-weight: 700;
      color: #0f172a;
      display: flex;
      align-items: center;
      gap: 6px;
    }
    .row-detail {
      font-size: 12px;
      color: #64748b;
      font-weight: 500;
      display: flex;
      flex-wrap: wrap;
      gap: 6px;
    }
    .metric-chip {
      background: #f8fafc;
      padding: 2px 6px;
      border-radius: 4px;
      border: 1px solid #e2e8f0;
      font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
      font-size: 11px;
      color: #334155;
    }
    .fail-badge {
      background: #fef2f2;
      color: #dc2626;
      border: 1.5px solid #fecaca;
      font-weight: 800;
      font-size: 12px;
      padding: 4px 10px;
      border-radius: 6px;
      letter-spacing: 0.5px;
      display: flex;
      align-items: center;
      gap: 4px;
      white-space: nowrap;
    }
    .verdict-box {
      margin-top: 2px;
      padding: 10px 12px;
      border-radius: 8px;
      background: #fef2f2;
      border: 1.5px solid #f87171;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 10px;
      opacity: 0.25;
      transition: opacity 0.4s ease;
    }
    .verdict-box.active {
      opacity: 1;
      box-shadow: 0 4px 12px rgba(220, 38, 38, 0.15);
    }
    .verdict-text {
      display: flex;
      flex-direction: column;
      gap: 2px;
    }
    .verdict-title {
      font-size: 13px;
      font-weight: 800;
      color: #991b1b;
      letter-spacing: -0.2px;
    }
    .verdict-sub {
      font-size: 11px;
      font-weight: 600;
      color: #b91c1c;
    }
    .verdict-icon {
      font-size: 22px;
      line-height: 1;
    }
    .controls {
      display: flex;
      align-items: center;
      justify-content: space-between;
      margin-top: auto;
      padding-top: 6px;
    }
    .btn-group {
      display: flex;
      align-items: center;
      gap: 6px;
    }
    .ctrl-btn {
      background: #ffffff;
      border: 1px solid #cbd5e1;
      color: #1e2945;
      padding: 5px 12px;
      border-radius: 6px;
      font-size: 12px;
      font-weight: 600;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      transition: background 0.15s ease;
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    .ctrl-btn:active {
      background: #f1f5f9;
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    .dots {
      display: flex;
      align-items: center;
      gap: 6px;
    }
    .dot {
      width: 8px;
      height: 8px;
      border-radius: 50%;
      background: #cbd5e1;
      cursor: pointer;
      transition: background 0.2s ease, transform 0.2s ease;
    }
    .dot.active {
      background: #dc2626;
      transform: scale(1.25);
    }
  </style>
</head>
<body>

  <div class="header-row">
    <div class="headline-pill">
      <span>📊 Statistical Audit</span>
      <span class="claim-tag">Claim: 87% Preference</span>
    </div>
  </div>

  <div class="scorecard">
    <div class="audit-row" id="row0" onclick="setAuditStep(0)">
      <div class="row-info">
        <div class="row-title">1. Sample Size</div>
        <div class="row-detail">
          <span class="metric-chip">n = 120</span>
          <span class="metric-chip">ME ≈ ±9.1%</span>
          <span>High Noise</span>
        </div>
      </div>
      <div class="fail-badge">✕ FAIL</div>
    </div>

    <div class="audit-row" id="row1" onclick="setAuditStep(1)">
      <div class="row-info">
        <div class="row-title">2. Demographic Sampling</div>
        <div class="row-detail">
          <span>Voluntary Forum Poll</span>
          <span class="metric-chip">Selection Bias</span>
        </div>
      </div>
      <div class="fail-badge">✕ FAIL</div>
    </div>

    <div class="audit-row" id="row2" onclick="setAuditStep(2)">
      <div class="row-info">
        <div class="row-title">3. Question Wording</div>
        <div class="row-detail">
          <span>Loaded Prompts</span>
          <span class="metric-chip">Response Bias</span>
        </div>
      </div>
      <div class="fail-badge">✕ FAIL</div>
    </div>
  </div>

  <div class="verdict-box" id="verdict">
    <div class="verdict-text">
      <div class="verdict-title">Unsound Generalization</div>
      <div class="verdict-sub">Cannot Infer National Opinion</div>
    </div>
    <div class="verdict-icon">🚫</div>
  </div>

  <div class="controls">
    <div class="btn-group">
      <button class="ctrl-btn" id="playBtn" onclick="togglePlay()">⏸ Pause</button>
      <button class="ctrl-btn" onclick="prevStep()">←</button>
      <button class="ctrl-btn" onclick="nextStep()">→</button>
    </div>
    <div class="dots">
      <div class="dot" id="dot0" onclick="setAuditStep(0)"></div>
      <div class="dot" id="dot1" onclick="setAuditStep(1)"></div>
      <div class="dot" id="dot2" onclick="setAuditStep(2)"></div>
      <div class="dot" id="dot3" onclick="setAuditStep(3)"></div>
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  </div>

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        document.getElementById('row1'),
        document.getElementById('row2')
      ];
      const verdict = document.getElementById('verdict');
      const dots = [
        document.getElementById('dot0'),
        document.getElementById('dot1'),
        document.getElementById('dot2'),
        document.getElementById('dot3')
      ];

      rows.forEach((r, idx) => {
        if (idx === currentStep) {
          r.className = 'audit-row active';
        } else if (idx < currentStep) {
          r.className = 'audit-row revealed';
        } else {
          r.className = 'audit-row';
        }
      });

      if (currentStep === 3) {
        verdict.className = 'verdict-box active';
      } else {
        verdict.className = 'verdict-box';
      }

      dots.forEach((d, idx) => {
        d.className = idx === currentStep ? 'dot active' : 'dot';
      });
    }

    function setAuditStep(step) {
      currentStep = step % totalSteps;
      updateUI();
    }

    function nextStep() {
      currentStep = (currentStep + 1) % totalSteps;
      updateUI();
    }

    function prevStep() {
      currentStep = (currentStep - 1 + totalSteps) % totalSteps;
      updateUI();
    }

    function togglePlay() {
      isPlaying = !isPlaying;
      const playBtn = document.getElementById('playBtn');
      if (isPlaying) {
        playBtn.textContent = '⏸ Pause';
        startTimer();
      } else {
        playBtn.textContent = '▶ Play';
        clearInterval(timer);
      }
    }

    function startTimer() {
      clearInterval(timer);
      timer = setInterval(() => {
        if (isPlaying) {
          nextStep();
        }
      }, 3000);
    }

    updateUI();
    startTimer();
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    }

    body {
      background-color: #f8f9fa;
      color: #1e2945;
      padding: 12px;
      display: flex;
      flex-direction: column;
      gap: 10px;
      min-height: 100%;
    }

    /* Formula Callout */
    .formula-banner {
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 10px;
      padding: 8px 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      font-size: 15px;
      font-weight: 600;
      color: #1e2945;
    }

    .math {
      font-family: 'Cambria Math', 'Times New Roman', serif;
      font-style: italic;
      font-weight: 700;
      color: #2563eb;
      background: #eff6ff;
      padding: 2px 8px;
      border-radius: 6px;
      font-size: 16px;
    }

    /* Comparison Grid */
    .comparison-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 10px;
      flex: 1;
    }

    @media (max-width: 440px) {
      .comparison-grid {
        grid-template-columns: 1fr;
      }
    }

    /* Column Cards */
    .sim-card {
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 12px;
      padding: 10px;
      display: flex;
      flex-direction: column;
      justify-content: space-between;
    }

    .card-head {
      display: flex;
      justify-content: space-between;
      align-items: center;
      margin-bottom: 6px;
    }

    .sample-tag {
      font-size: 14px;
      font-weight: 700;
      color: #1e2945;
    }

    .moe-badge {
      font-size: 13px;
      font-weight: 700;
      padding: 2px 7px;
      border-radius: 6px;
    }

    .moe-badge.coral {
      background: #fee2e2;
      color: #ef4444;
    }

    .moe-badge.blue {
      background: #dbeafe;
      color: #2563eb;
    }

    /* Canvas / Visualization Area */
    .chart-container {
      position: relative;
      height: 120px;
      background: #f8fafc;
      border-radius: 8px;
      border: 1px dashed #cbd5e1;
      overflow: hidden;
    }

    svg {
      width: 100%;
      height: 100%;
      display: block;
    }

    /* Control Area */
    .controls {
      display: flex;
      justify-content: center;
      margin-top: 2px;
    }

    .btn-resample {
      background: #2563eb;
      color: #ffffff;
      border: none;
      border-radius: 8px;
      padding: 8px 18px;
      font-size: 14px;
      font-weight: 600;
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 6px;
      transition: background-color 0.2s, opacity 0.2s;
    }

    .btn-resample:active {
      background: #1d4ed8;
    }
  </style>
</head>
<body>

  
  <div class="formula-banner">
    <span>Margin of Error:</span>
    <span class="math">ME ≈ 1 / √n</span>
  </div>

  
  <div class="comparison-grid">
    
    <div class="sim-card">
      <div class="card-head">
        <span class="sample-tag">n = 15</span>
        <span class="moe-badge coral">± 25%</span>
      </div>
      <div class="chart-container">
        <svg id="svgSmall" viewBox="0 0 200 120">
          
          <rect x="50" y="10" width="100" height="100" fill="#fee2e2" rx="4" opacity="0.6" />
          
          
          <line x1="100" y1="5" x2="100" y2="115" stroke="#94a3b8" stroke-width="1.5" stroke-dasharray="3,3" />
          <line x1="20" y1="100" x2="180" y2="100" stroke="#cbd5e1" stroke-width="1" />
          
          
          <text x="20" y="112" font-size="9" fill="#94a3b8" text-anchor="middle">0%</text>
          <text x="100" y="112" font-size="9" fill="#1e2945" font-weight="bold" text-anchor="middle">50%</text>
          <text x="180" y="112" font-size="9" fill="#94a3b8" text-anchor="middle">100%</text>

          
          <g id="dotsSmall"></g>
        </svg>
      </div>
    </div>

    
    <div class="sim-card">
      <div class="card-head">
        <span class="sample-tag">n = 1,000</span>
        <span class="moe-badge blue">± 3.1%</span>
      </div>
      <div class="chart-container">
        <svg id="svgLarge" viewBox="0 0 200 120">
          
          <rect x="93.8" y="10" width="12.4" height="100" fill="#dbeafe" rx="2" opacity="0.8" />
          
          
          <line x1="100" y1="5" x2="100" y2="115" stroke="#94a3b8" stroke-width="1.5" stroke-dasharray="3,3" />
          <line x1="20" y1="100" x2="180" y2="100" stroke="#cbd5e1" stroke-width="1" />
          
          
          <text x="20" y="112" font-size="9" fill="#94a3b8" text-anchor="middle">0%</text>
          <text x="100" y="112" font-size="9" fill="#1e2945" font-weight="bold" text-anchor="middle">50%</text>
          <text x="180" y="112" font-size="9" fill="#94a3b8" text-anchor="middle">100%</text>

          
          <g id="dotsLarge"></g>
        </svg>
      </div>
    </div>
  </div>

  
  <div class="controls">
    <button class="btn-resample" onclick="simulatePolls()">
      <span>✦</span> Simulate Samples
    </button>
  </div>

  <script>
    // Standard normal generator (Box-Muller)
    function randNormal() {
      let u = 0, v = 0;
      while (u === 0) u = Math.random();
      while (v === 0) v = Math.random();
      return Math.sqrt(-2.0 * Math.log(u)) * Math.cos(2.0 * Math.PI * v);
    }

    function simulatePolls() {
      const gSmall = document.getElementById('dotsSmall');
      const gLarge = document.getElementById('dotsLarge');
      gSmall.innerHTML = '';
      gLarge.innerHTML = '';

      const pTrue = 0.50;
      const totalPoints = 14;

      // Small sample: n=15 -> SE ≈ sqrt(0.5*0.5/15) ≈ 0.129
      const seSmall = Math.sqrt(0.25 / 15);
      // Large sample: n=1000 -> SE ≈ sqrt(0.5*0.5/1000) ≈ 0.0158
      const seLarge = Math.sqrt(0.25 / 1000);

      // SVG coordinates: 0% = x:20, 100% = x:180 (scale = 160 units per 100%)
      function valToX(val) {
        const clamped = Math.max(0, Math.min(1, val));
        return 20 + clamped * 160;
      }

      for (let i = 0; i < totalPoints; i++) {
        const y = 20 + i * 5.2;

        // Small sample estimation
        const pHatSmall = pTrue + randNormal() * seSmall;
        const xSmall = valToX(pHatSmall);

        const circleSmall = document.createElementNS('http://www.w3.org/2000/svg', 'circle');
        circleSmall.setAttribute('cx', xSmall);
        circleSmall.setAttribute('cy', y);
        circleSmall.setAttribute('r', '4');
        circleSmall.setAttribute('fill', '#ef4444');
        circleSmall.setAttribute('opacity', '0.85');
        circleSmall.style.transition = 'all 0.35s ease';
        gSmall.appendChild(circleSmall);

        // Large sample estimation
        const pHatLarge = pTrue + randNormal() * seLarge;
        const xLarge = valToX(pHatLarge);

        const circleLarge = document.createElementNS('http://www.w3.org/2000/svg', 'circle');
        circleLarge.setAttribute('cx', xLarge);
        circleLarge.setAttribute('cy', y);
        circleLarge.setAttribute('r', '4');
        circleLarge.setAttribute('fill', '#2563eb');
        circleLarge.setAttribute('opacity', '0.85');
        circleLarge.style.transition = 'all 0.35s ease';
        gLarge.appendChild(circleLarge);
      }
    }

    // Initial run
    simulatePolls();
  </script>
</body>
</html>

Constructing and Interpreting Scatter Plots

Calculating and Interpreting Sample Covariance

Calculating Pearson's Correlation Coefficient (r)

Properties and Interpretations of the Correlation Coefficient

Evaluating the Impact of Outliers on Correlation

Understanding the Coefficient of Determination (r²)

Distinguishing Correlation from Causation

math

Bivariate Association: Covariance and Correlation Analysis

The Definition and Formula of Conditional Probability

Calculating Conditional Probabilities from Contingency Tables

Formal Tests for Statistical Independence

Using Tree Diagrams to Calculate P(A|B)

The Law of Total Probability

Bayes' Theorem: Inverting Conditional Probabilities

Medical Testing, Sensitivity, Specificity, and False Positives

Conditional Probability, Tree Diagrams, and Bayes' Theorem

Probability Sampling Methods: Simple Random, Stratified, Cluster, and Systematic

Non-Probability Sampling and Selection Bias

Principles of Experimental Design: Control, Randomization, and Replication

Placebo Controls, Blinding, and Randomized Block Designs

Designing Matched Pairs Experiments

Critiquing Sampling Methods in Published Studies

Statistical Study Design and Random Sampling Methodologies

Understanding Margin of Error and Confidence in Media Polls

Detecting Misleading Visualizations and Distorted Graphs

Analyzing Simpson's Paradox in Aggregate Data

Statistical Fallacies: Gambler's Fallacy and Prosecutor's Fallacy

Drawing Valid Inferences and Bounding Generalizations

Comprehensive Case Study: Auditing a Published Research Report

Critiquing Media Claims, Statistical Fallacies, and Inferential Reasoning

Diseño de experimentos aleatorios en ciencias

Probabilidad clásica y axiomas de Kolmogorov

Regla de la adición y eventos mutuamente excluyentes

Probabilidad condicional y tablas de contingencia

Independencia de eventos y regla de la multiplicación

Teorema de la probabilidad total y particiones

Teorema de Bayes y actualización de probabilidades

Variables aleatorias discretas y función de probabilidad

Esperanza matemática y varianza de una variable aleatoria

Distribución binomial: ensayos de Bernoulli y parámetros

Probabilidad clásica, condicional y distribuciones

Interpretación de datos en medios de comunicación

Detección de sesgos en gráficas, escalas y encuestas

Métodos de muestreo probabilístico: aleatorio, estratificado y por conglomerados

OGM.12.STA.3

Aligned learning resources

Related diagrams