Mathematics 9709 · AS & A Level · Sampling and estimation

Sampling and estimation — practice question

For a data set with values $x$, the summaries are $\sum (x-25)=133$, $\sum (x-25)^2=3762$. The mean, $\bar{x}$, is $28.325$.

(i)[4]

Determine the standard deviation of $x$.

(ii)[2]

Determine $\sum x^2$.

Worked solution & mark scheme

This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Apply equation $133/n + 25 = 28.325$” …