## Question 7(i):

| Answer | Mark | Guidance |
|--------|------|----------|
| Correct stem (up or down) | B1 | Correct stem, up or down |
| Correct Anvils labelled on left, leaves in order right to left and lined up vertically, no commas | B1 | Correct Anvils labelled on left, leaves in order from right to left and lined up vertically, no commas |
| Correct Brecons labelled on right, leaves left to right, lined up vertically, no commas | B1 | Correct Brecons labelled on same diagram on right hand side in order from left to right and lined up vertically, no commas |
| Correct key, not split, both teams, at least one with cm | B1 | Correct key, not split, both teams, at least one with cm |

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## Question 7(ii):

| Answer | Mark | Guidance |
|--------|------|----------|
| Median $= 173$ | B1 | Correct median (or Q2) |
| $LQ = 169$; $UQ = 181$, $IQR = 181 - 169$ | M1 | Either $UQ = 181 \pm 4$, or $LQ = 169 \pm 4$ and evaluating $UQ - LQ$ |
| $= 12$ | A1 | Correct answer from $181$ and $169$ only |

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## Question 7(iii):

| Answer | Mark | Guidance |
|--------|------|----------|
| $\sum x = 1923 + 166 + 172 + 182 = 2443$; $\sum x^2 = 337221 + 166^2 + 172^2 + 182^2 = 427485$ | M1 | Correct unsimplified expression for $\sum x$ and $\sum x^2$, may be implied |
| Mean $= \frac{\sum x}{14} = \frac{2443}{14} = 174.5$ | M1 | Correct unsimplified mean |
| Variance $= \frac{\sum x^2}{14} - \left(\frac{\sum x}{14}\right)^2 = \frac{427485}{14} - \left(\frac{2443}{14}\right)^2$ | M1 | Correct unsimplified variance using $14$, their $\sum x$ and their $\sum x^2$, not using $1923$ and/or $337221$ |
| $S_d = 9.19$ | A1 | Correct answer |