Mathematics 9709 · AS & A Level · Sampling and estimation

Sampling and estimation — practice question

The values of height, $x$ cm, for a set of 82 children are given by: $\Sigma(x - 130) = -287$, standard deviation of $x = 6.9$.

(a)[2]

Find the mean height.

(b)[2]

Find $\Sigma(x - 130)^2$.

Worked solution & mark scheme

This 4-mark question has a full step-by-step worked solution and mark scheme. One marking point: “$\bar{x}=130-\frac{287}{82}$ or equivalent seen” …