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  <title>Fair Testing in Chemical Rates: Compromised vs Controlled</title>
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</head>
<body>

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      <button class="tab active" id="tabAll">Both Views</button>
      <button class="tab" id="tabFlawed">Compromised</button>
      <button class="tab" id="tabFair">Fair Test</button>
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      <div class="panel-title bad">✕ Compromised Investigation</div>
      <div class="env-indicator flawed">⚠️ Uncontrolled Variable: Temperature</div>
      
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          <div class="temp-tag temp-20">20°C</div>
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              <div class="mg-strip"></div>
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          <div class="conc-label">0.5 M HCl</div>
        </div>

        
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          <div class="temp-tag temp-50">50°C ⚠️</div>
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              <div class="bubble fast-4"></div>
            </div>
          </div>
          <div class="conc-label">1.0 M HCl</div>
        </div>
      </div>

      <div class="status-badge badge-bad">
        <strong>Uncontrolled Confounding Variable</strong>
        Cannot prove concentration caused speed increase.
      </div>
    </div>

    
    <div class="card-panel" id="panelFair">
      <div class="panel-title good">✓ Controlled Fair Test</div>
      <div class="env-indicator fair">✓ Controlled Variable: Constant Temp</div>

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        <div class="water-bath-bg">
          <div class="bath-tag-badge">Thermostatted Water Bath (25°C)</div>
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          <div class="temp-tag temp-25">25°C</div>
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          <div class="conc-label">0.5 M HCl</div>
        </div>

        
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          <div class="temp-tag temp-25">25°C</div>
          <div class="beaker">
            <div class="liquid conc-2">
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              <div class="bubble fair-fast-2"></div>
              <div class="bubble fair-fast-3"></div>
            </div>
          </div>
          <div class="conc-label">1.0 M HCl</div>
        </div>
      </div>

      <div class="status-badge badge-good">
        <strong>Valid Fair Test</strong>
        Constant 25°C guarantees only concentration changes rate.
      </div>
    </div>
  </div>

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</html>

Identifying Weaknesses in Experimental Methodology

<!DOCTYPE html>
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      color: #1e293b;
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      margin-bottom: 6px;
      text-align: center;
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      width: 100%;
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      stroke-width: 1.5;
      stroke-dasharray: 4, 4;
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    .point-optimum { fill: #2563eb; stroke: #fff; stroke-width: 2; }

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      animation: pulseDash 3s ease-in-out infinite;
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      animation: floatBadge 3s ease-in-out infinite;
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      0%, 100% { opacity: 0.45; }
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  </style>
</head>
<body>

  <div class="graphs-container">
    
    <div class="graph-pane">
      <div class="graph-title bad">Graph A: 20°C Intervals (Wide)</div>
      <svg viewBox="0 0 250 180" aria-label="Graph A: 20 degree Celsius intervals missing optimum rate">
        
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        <line x1="32" y1="145" x2="32" y2="20" class="axis" />

        
        <text x="135" y="172" text-anchor="middle" class="axis-label">Temperature (°C)</text>
        <text x="12" y="82" text-anchor="middle" transform="rotate(-90 12 82)" class="axis-label">Rate</text>

        
        <text x="32" y="158" text-anchor="middle" class="tick-text">0</text>
        <text x="96.6" y="158" text-anchor="middle" class="tick-text">20</text>
        <text x="161.3" y="158" text-anchor="middle" class="tick-text">40</text>
        <text x="226" y="158" text-anchor="middle" class="tick-text">60</text>

        
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        <circle cx="96.6" cy="122" r="3.5" class="point-bad" />
        <circle cx="161.3" cy="73" r="3.5" class="point-bad" />
        <circle cx="226" cy="145" r="3.5" class="point-bad" />

        
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        </g>
      </svg>
    </div>

    
    <div class="graph-pane">
      <div class="graph-title good">Graph B: 5°C Intervals (Narrow)</div>
      <svg viewBox="0 0 250 180" aria-label="Graph B: 5 degree Celsius intervals showing true optimum peak">
        
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        <line x1="32" y1="145" x2="32" y2="20" class="axis" />

        
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        <text x="12" y="82" text-anchor="middle" transform="rotate(-90 12 82)" class="axis-label">Rate</text>

        
        <text x="32" y="158" text-anchor="middle" class="tick-text">0</text>
        <text x="96.6" y="158" text-anchor="middle" class="tick-text">20</text>
        <text x="161.3" y="158" text-anchor="middle" class="tick-text">40</text>
        <text x="226" y="158" text-anchor="middle" class="tick-text">60</text>

        
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        <circle cx="112.8" cy="108" r="2.5" class="point-good" />
        <circle cx="129.0" cy="85" r="2.5" class="point-good" />
        <circle cx="145.1" cy="46" r="2.5" class="point-good" />
        <circle cx="161.3" cy="73" r="2.5" class="point-good" />
        <circle cx="177.5" cy="128" r="2.5" class="point-good" />
        <circle cx="193.7" cy="145" r="2.5" class="point-good" />

        
        <circle cx="151.7" cy="28" r="4.5" class="point-optimum" />

        
        <rect x="90" y="15" width="86" height="18" rx="4" fill="#eff6ff" stroke="#2563eb" stroke-width="1" />
        <text x="133" y="27.5" text-anchor="middle" font-size="9.5" font-weight="700" fill="#1d4ed8">Optimum: 37°C</text>
      </svg>
    </div>
  </div>

</body>
</html>

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      display: inline-flex;
      align-items: center;
      gap: 4px;
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      font-weight: 700;
      padding: 3px 8px;
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      align-self: flex-start;
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      background: #fef2f2;
      color: #dc2626;
      border: 1px solid #fecaca;
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      background: #f0fdf4;
      color: #16a34a;
      border: 1px solid #bbf7d0;
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      display: flex;
      align-items: center;
      justify-content: center;
      padding: 12px 4px;
      min-height: 110px;
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      font-weight: 600;
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      font-size: 12px;
      font-weight: 600;
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    .outcome-bad {
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      color: #991b1b;
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      color: #166534;
      border: 1px solid #86efac;
    }
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      font-size: 13px;
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      font-weight: 600;
      color: #334155;
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    .fraction {
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      align-items: center;
      vertical-align: middle;
      font-size: 11px;
      line-height: 1.1;
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    .fraction .num {
      border-bottom: 1.5px solid #334155;
      padding: 0 4px 1px;
    }
    .fraction .den {
      padding: 1px 4px 0;
    }
    .highlight-mean {
      background: #22c55e;
      color: #ffffff;
      padding: 3px 8px;
      border-radius: 5px;
      font-weight: 700;
      font-size: 12px;
    }
  </style>
</head>
<body>

  <div class="grid-container">
    
    <div class="panel">
      <div class="badge badge-bad">⚠️ Sample size <i>n</i> = 1</div>
      
      <div class="scene">
        <div class="single-plant">
          🥀
          <span class="subtext">Seed defect</span>
        </div>
      </div>

      <div class="outcome outcome-bad">
        Misleading: "Drug kills plants"
      </div>
    </div>

    
    <div class="panel">
      <div class="badge badge-good">✓ Sample size <i>n</i> = 10 (×3 repeats)</div>
      
      <div class="scene">
        <div class="pot-grid">
          <div class="plant-item">🌱<span class="subtext">8.4</span></div>
          <div class="plant-item">🌱<span class="subtext">8.5</span></div>
          <div class="plant-item">🌱<span class="subtext">8.3</span></div>
          <div class="plant-item">🌱<span class="subtext">8.4</span></div>
          <div class="plant-item">🌱<span class="subtext">8.6</span></div>
          <div class="plant-item">🌱<span class="subtext">8.3</span></div>
          <div class="plant-item">🌱<span class="subtext">8.5</span></div>
          <div class="plant-item">🌱<span class="subtext">8.4</span></div>
          <div class="plant-item">🌱<span class="subtext">8.2</span></div>
          <div class="plant-item anomaly">🥀<span class="subtext">0.0</span></div>
        </div>
      </div>

      <div class="outcome outcome-good">
        Anomaly excluded • Reliable mean
      </div>
    </div>
  </div>

  
  <div class="formula-bar">
    <div class="formula">
      <span>Mean =</span>
      <div class="fraction">
        <span class="num">Sum of concordant values</span>
        <span class="den">Number of trials (9)</span>
      </div>
    </div>
    <div class="highlight-mean">Mean = 8.4 cm</div>
  </div>

</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>
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      gap: 6px;
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      background: #fff5f5;
      border: 1px solid #fed7d7;
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    .panel-fix {
      background: #f0fdf4;
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    .panel-label {
      font-size: 11px;
      font-weight: 700;
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    .panel-flaw .panel-label { color: #dc2626; }
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    .panel-text {
      font-size: 13px;
      line-height: 1.4;
      color: #334155;
      font-weight: 500;
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    .visual-pill {
      margin-top: auto;
      background: #ffffff;
      border-radius: 6px;
      padding: 6px 8px;
      font-size: 11px;
      font-weight: 600;
      color: #475569;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      border: 1px dashed #cbd5e1;
    }

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        grid-template-columns: 1fr;
      }
      .breakdown-box {
        min-height: auto;
      }
      .panel-text {
        font-size: 12px;
      }
    }
  </style>
</head>
<body>

  
  <div class="method-card">
    <div class="method-title">Student's Experimental Method</div>
    <span>"To test enzyme activity, I </span>
    <span class="pin pin-amber" id="pin-1" data-flaw="1">🫧 counted bubbles</span>
    <span> produced at </span>
    <span class="pin pin-red" id="pin-0" data-flaw="0">🌡️ 20°C and 40°C</span>
    <span>, testing </span>
    <span class="pin pin-purple" id="pin-2" data-flaw="2">⏱️ once per temperature</span>
    <span>."</span>
  </div>

  
  <div class="nav-tabs">
    <button class="tab-btn active" id="tab-0">
      <span class="dot-badge dot-red"></span> Temp Range
    </button>
    <button class="tab-btn" id="tab-1">
      <span class="dot-badge dot-amber"></span> Bubbles
    </button>
    <button class="tab-btn" id="tab-2">
      <span class="dot-badge dot-purple"></span> Repeats
    </button>
  </div>

  
  <div class="breakdown-box">
    <div class="comparison-grid">
      
      <div class="panel-flaw">
        <div class="panel-label">✕ Flaw</div>
        <div class="panel-text" id="flaw-desc">Only 2 data points; cannot determine trend or optimum temperature.</div>
        <div class="visual-pill" id="flaw-vis">⚠️ 2 Points: 20°C &amp; 40°C</div>
      </div>

      
      <div class="panel-fix">
        <div class="panel-label">✓ Fix</div>
        <div class="panel-text" id="fix-desc">Test 5+ temperatures in 5°C intervals (10°C to 50°C).</div>
        <div class="visual-pill" id="fix-vis">📈 10, 15, 20, 25, 30... 50°C</div>
      </div>
    </div>
  </div>

  <script>
    const flawData = [
      {
        flaw: "Inadequate range & interval (2 data points; cannot find optimum).",
        flawVis: "⚠️ Only 2 points (20°C & 40°C)",
        fix: "Test at least 5 temperatures in 5°C intervals from 10°C to 50°C.",
        fixVis: "📈 10°, 15°, 20°, 25°, 30°... 50°C"
      },
      {
        flaw: "Bubbles vary in volume (imprecise dependent variable).",
        flawVis: "🫧 Uneven bubble sizes",
        fix: "Collect gas in an inverted measuring cylinder or gas syringe.",
        fixVis: "🧪 Measured Gas Volume (cm³)"
      },
      {
        flaw: "Single trial (no repeats to identify anomalies or calculate mean).",
        flawVis: "⚠️ 1 Trial per temp",
        fix: "Perform at least 3 repeats per temperature and calculate a mean.",
        fixVis: "📊 3 Repeats + Mean (x̄)"
      }
    ];

    let currentIdx = 0;

    function setFlaw(index) {
      currentIdx = index;
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      document.getElementById('fix-vis').textContent = data.fixVis;

      // Update active tabs and pins
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      document.getElementById(`tab-${i}`).addEventListener('click', () => setFlaw(i));
      document.getElementById(`pin-${i}`).addEventListener('click', () => setFlaw(i));
    }

    // Initialize first state
    setFlaw(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 {
      background: #f8f9fa;
      color: #1e2945;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      padding: 12px;
      display: flex;
      flex-direction: column;
      gap: 12px;
      width: 100%;
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    .grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 10px;
      width: 100%;
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    @media (max-width: 540px) {
      .grid {
        grid-template-columns: 1fr;
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    }

    .tile {
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 10px;
      padding: 12px 10px;
      display: flex;
      flex-direction: column;
      align-items: center;
      text-align: center;
      gap: 8px;
    }

    .tile-title {
      font-size: 14px;
      font-weight: 700;
      color: #1e2945;
      line-height: 1.2;
      min-height: 34px;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .visual-box {
      width: 100%;
      height: 110px;
      background: #f8fafc;
      border-radius: 8px;
      border: 1px solid #edf2f7;
      display: flex;
      align-items: center;
      justify-content: center;
      position: relative;
      overflow: hidden;
    }

    .badge {
      font-size: 12px;
      font-weight: 600;
      padding: 5px 8px;
      border-radius: 6px;
      line-height: 1.2;
      width: 100%;
    }

    .badge-red {
      background: #fee2e2;
      color: #b91c1c;
      border: 1px solid #fecaca;
    }

    .badge-amber {
      background: #fef3c7;
      color: #b45309;
      border: 1px solid #fde68a;
    }

    .badge-teal {
      background: #ccfbf1;
      color: #0f766e;
      border: 1px solid #99f6e4;
    }

    /* SVG Styling */
    svg {
      display: block;
      width: 100%;
      height: 100%;
    }
  </style>
</head>
<body>

  <div class="grid">
    
    <div class="tile">
      <div class="tile-title">Uncontrolled<br>Variables</div>
      <div class="visual-box">
        <svg viewBox="0 0 160 110">
          
          <line x1="80" y1="45" x2="80" y2="92" stroke="#94a3b8" stroke-width="4" stroke-linecap="round" />
          <path d="M 55 92 L 105 92" stroke="#94a3b8" stroke-width="4" stroke-linecap="round" />
          <polygon points="80,45 74,56 86,56" fill="#64748b" />
          
          
          
          <line x1="25" y1="33" x2="135" y2="57" stroke="#475569" stroke-width="3" stroke-linecap="round" />
          
          
          <line x1="25" y1="33" x2="15" y2="58" stroke="#cbd5e1" stroke-width="1.5" />
          <line x1="25" y1="33" x2="35" y2="58" stroke="#cbd5e1" stroke-width="1.5" />
          <path d="M 12 58 Q 25 64 38 58" fill="none" stroke="#64748b" stroke-width="2.5" stroke-linecap="round" />
          
          <rect x="20" y="47" width="10" height="10" rx="2" fill="#3b82f6" />
          <text x="25" y="55" font-size="8" font-weight="bold" fill="#ffffff" text-anchor="middle">IV</text>

          
          <line x1="135" y1="57" x2="125" y2="82" stroke="#cbd5e1" stroke-width="1.5" />
          <line x1="135" y1="57" x2="145" y2="82" stroke="#cbd5e1" stroke-width="1.5" />
          <path d="M 122 82 Q 135 88 148 82" fill="none" stroke="#64748b" stroke-width="2.5" stroke-linecap="round" />
          
          <rect x="127" y="71" width="10" height="10" rx="2" fill="#3b82f6" />
          <text x="132" y="79" font-size="8" font-weight="bold" fill="#ffffff" text-anchor="middle">IV</text>
          
          <rect x="138" y="69" width="8" height="12" rx="2" fill="#ef4444" stroke="#b91c1c" stroke-width="1" stroke-dasharray="2,1" />
          <text x="142" y="78" font-size="8" font-weight="bold" fill="#ffffff" text-anchor="middle">?</text>
        </svg>
      </div>
      <div class="badge badge-red">Destroys<br>Validity</div>
    </div>

    
    <div class="tile">
      <div class="tile-title">Inadequate<br>Intervals</div>
      <div class="visual-box">
        <svg viewBox="0 0 160 110">
          
          <line x1="22" y1="90" x2="145" y2="90" stroke="#cbd5e1" stroke-width="2" />
          <line x1="22" y1="90" x2="22" y2="18" stroke="#cbd5e1" stroke-width="2" />
          
          
          
          <path d="M 30 80 Q 80 10 135 80" fill="none" stroke="#f59e0b" stroke-width="2" stroke-dasharray="3,3" opacity="0.85" />
          
          
          <circle cx="80" cy="27.5" r="3.5" fill="#f59e0b" />
          <text x="80" y="19" font-size="9" font-weight="700" fill="#d97706" text-anchor="middle">Peak?</text>

          
          <polyline points="30,80 82.5,78 135,80" fill="none" stroke="#1e2945" stroke-width="2" />
          
          
          <circle cx="30" cy="80" r="4.5" fill="#1e2945" />
          <circle cx="82.5" cy="78" r="4.5" fill="#1e2945" />
          <circle cx="135" cy="80" r="4.5" fill="#1e2945" />
        </svg>
      </div>
      <div class="badge badge-amber">Misses Trends<br>& Optima</div>
    </div>

    
    <div class="tile">
      <div class="tile-title">Insufficient<br>Sample Size</div>
      <div class="visual-box">
        <svg viewBox="0 0 160 110">
          
          <line x1="68" y1="15" x2="68" y2="95" stroke="#e2e8f0" stroke-width="1.5" stroke-dasharray="3,3" />

          
          <text x="35" y="24" font-size="11" font-weight="700" fill="#ef4444" text-anchor="middle">N = 1</text>
          
          <rect x="27" y="32" width="16" height="42" rx="8" fill="#ffffff" stroke="#ef4444" stroke-width="2" />
          
          <path d="M 29 54 Q 35 52 41 54 L 41 66 A 6 6 0 0 1 29 66 Z" fill="#fee2e2" />
          <text x="35" y="93" font-size="13" font-weight="bold" fill="#ef4444" text-anchor="middle">?</text>

          
          <text x="114" y="24" font-size="11" font-weight="700" fill="#0d9488" text-anchor="middle">N = 5</text>
          
          
          
          <rect x="76" y="36" width="10" height="34" rx="5" fill="#ffffff" stroke="#0d9488" stroke-width="1.5" />
          <path d="M 77.5 52 L 84.5 52 L 84.5 65 A 3.5 3.5 0 0 1 77.5 65 Z" fill="#ccfbf1" />

          
          <rect x="91" y="36" width="10" height="34" rx="5" fill="#ffffff" stroke="#0d9488" stroke-width="1.5" />
          <path d="M 92.5 51 L 99.5 51 L 99.5 65 A 3.5 3.5 0 0 1 92.5 65 Z" fill="#ccfbf1" />

          
          <rect x="106" y="36" width="10" height="34" rx="5" fill="#ffffff" stroke="#0d9488" stroke-width="1.5" />
          <path d="M 107.5 58 L 114.5 58 L 114.5 65 A 3.5 3.5 0 0 1 107.5 65 Z" fill="#ccfbf1" />

          
          <rect x="121" y="36" width="10" height="34" rx="5" fill="#ffffff" stroke="#0d9488" stroke-width="1.5" />
          <path d="M 122.5 52 L 129.5 52 L 129.5 65 A 3.5 3.5 0 0 1 122.5 65 Z" fill="#ccfbf1" />

          
          <rect x="136" y="36" width="10" height="34" rx="5" fill="#ffffff" stroke="#0d9488" stroke-width="1.5" />
          <path d="M 137.5 53 L 144.5 53 L 144.5 65 A 3.5 3.5 0 0 1 137.5 65 Z" fill="#ccfbf1" />

          <text x="114" y="93" font-size="12" font-weight="bold" fill="#0d9488" text-anchor="middle">✓ Mean</text>
        </svg>
      </div>
      <div class="badge badge-teal">Allows Anomalies<br>to Skew Results</div>
    </div>
  </div>

</body>
</html>

UK-GCSE-SCIENCE-WS-2-07

Aligned learning resources

Related diagrams