Stav is studying the large data set for September 2015 - Edexcel - A-Level Maths Statistics - Question 3 - 2021 - Paper 1

To find the mean Daily Mean Pressure (ar{x}), use the formula:

ar{x} = \frac{\sum y}{n} + 1010 where (\sum y = 214) and (n = 30).

Calculating it gives:

$\bar{x} = \frac{214}{30} + 1010 \approx 1017.13\text{ (rounded to 1017)}$

The standard deviation ( σ) can be computed using:

$σ = \sqrt{\frac{\sum x^2}{n} - \bar{x}^2}$ Substituting the values:

• (\sum x^2 = 5912)
• (\bar{x} = 1017.13)
• (n = 30)

Calculating:

$σ = \sqrt{\frac{5912}{30} - (1017.13)^2}$

This yields:

$σ \approx 12.09\text{ (rounded to 12.1)}$

The regions of pressure indicate that:

• Hurn is located near the low-pressure area, so wind circulates clockwise: High Pressure (Hurn)
• Therefore, we can conclude the wind directions:
• Heathrow (N - high pressure), Hurn (E - low pressure), Leuchars (W - low pressure).

Thus, the placements based on pressure zones are:

• Heathrow: N
• Hurn: E
• Leuchars: W