Mathematics 9709 · AS & A Level · Sampling and estimation

Sampling and estimation — practice question

Swati recorded the lengths, $x$ cm, of $18$ stick insects and obtained $\Sigma x^2 = 967$. If the mean length is $\frac{58}{9}$ cm,

(main)[5]

work out the values of $\Sigma(x - 5)$ and $\Sigma(x - 5)^2$.

Worked solution & mark scheme

This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Hence $\Sigma(x-5)=116-18\times5=26$” …