Keith records the amount of rainfall, in mm, at his school, each day for a week - Edexcel - A-Level Maths Statistics - Question 2 - 2011 - Paper 1

To find the total amount of rainfall for the 28 days, we first add Keith's recorded rainfall:

$2.8 + 5.6 + 2.3 + 9.4 + 0.0 + 0.5 + 1.8 = 22.4 \text{ mm}$

Next, we add the total rainfall recorded by Jenny:

( 84.6 \text{ mm} )

Now, the total rainfall over the 28 days is:

$22.4 + 84.6 = 107 \text{ mm}$

To find the mean amount of rainfall, we divide the total by the number of days:

$\text{Mean} = \frac{107}{28} \approx 3.82 \text{ mm}$