| Part | Answer/Working | Marks | Guidance |
|------|---|---|---|
| (a) | Hectopascal or hPa | B1 | B1 for "hectopascal" or hPa (condone pascals, allow millibars or mb) o.e. **Do NOT allow** kPa or kilopascals or Pa on its own |
| (b) | $\bar{x} = \bar{y} + 1010$ or $\frac{214}{30} + 1010$ | M1 | M1 for a strategy to find $\bar{x}$ Allow an attempt to find $\sum x$ that gets as far as $\sum x = \sum y - 30 \times 1010 = [30 \text{ 514}]$ |
| | $= 1017.1333...$ awrt $\mathbf{1017}$ | A1 | A1 for awrt 1017 (accept 1020) [Ignore incorrect units] |
| (c) | $\sigma_x = \sigma_y$ (or statement that standard deviation is not affected by this type of coding) | M1 | 1st M1 for an overall strategy using the fact $\sigma_x = \sigma_y$ (can be implied by correct **final ans**) or for $\sum x = 30 \text{ 514}$ and $\sum x^2 = 31 \text{ 041192}$ (both seen and correct) |
| | $[\sigma_y] = \sqrt{\frac{5912}{30} - ("7.13[33...]")^2}$ or $\sqrt{146.1822...}$ | M1 | 2nd M1 for a correct expression (with $\sqrt{}$)(ft their $\bar{y}$ to 3sf) allow awrt 146 for 146.1822... or for correct expression in $x$ can ft their $\sum x > 30 \text{ 000}$ or their answer to (b) |
| | $= 12.0905...$ awrt $\mathbf{12.1}$ | A1 | A1 (dep on 2nd M1) for awrt 12.1 [Ignore incorrect units] |
| (d) | High pressure (since approx. mean + sd) so clockwise. Locations are (from North to South): Leuchars, Heathrow, Hurn. Wind direction is direction wind blows **from**. So: Heathrow (NE) Hurn (E) Leuchars (W) | B1, B1 | 1st B1 for at least one of these reasons (these 2 lines) clearly stated (may see diagram). Need "high pressure" and "clockwise" to score on 1st line. Contradictory statements B0 e.g. correct N~S list but say "anticlockwise". 2nd B1 (indep of 1st B1) for deducing the 3 correct directions either in the table or stated as above. If the answers in table and text are different we take the table (as question says). |

**FYI Notes:**

| Item | Note |
|------|------|
| 1 hPa = 100 Pa; 10hPa = 1 kPa; 1Pa = 1 Nm⁻² | |
| (a) | B1 for "hectopascal" or hPa (condone pascals, allow millibars or mb) o.e. Do NOT allow kPa or kilopascals or Pa on its own |
| (b) | M1 for a strategy to find $\bar{x}$. Allow an attempt to find $\sum x$ that gets as far as $\sum x = \sum y - 30 \times 1010 = [30 \text{ 514}]$. A1 for awrt 1017 (accept 1020) [Ignore incorrect units] |
| (c) | 1st M1 for an overall strategy using the fact $\sigma_x = \sigma_y$ (can be implied by correct final ans) or for $\sum x = 30 \text{ 514}$ and $\sum x^2 = 31 \text{ 041192}$ (both seen and correct). 2nd M1 for a correct expression (with $\sqrt{}$)(ft their $\bar{y}$ to 3sf) allow awrt 146 for 146.1822... or for correct expression in $x$ can ft their $\sum x > 30 \text{ 000}$ or their answer to (b). A1 (dep on 2nd M1) for awrt 12.1 [Ignore incorrect units]. **Final ans of awrt 12.1 scores 3/3 but if they then adjust for $x$ e.g. add 1010 (M0M1A1)** |
| (d) | 1st B1 for at least one of these reasons (these 2 lines) clearly stated (may see diagram). Need "high pressure" and "clockwise" to score on 1st line. Contradictory statements B0 e.g. correct N~S list but say "anticlockwise". 2nd B1 (indep of 1st B1) for deducing the 3 correct directions either in the table or stated as above. If the answers in table and text are different we take the table (as question says). |