(main)[4]
Find the variance of the speeds and then use it to obtain the value of $\sum x^2$.
Mathematics 9709 · AS & A Level · Sampling and estimation
Sampling and estimation — practice question
For the 22 cars that passed a particular point, the speeds, $x$ kilometres per hour, were summarised by the information $\sum (x - 50) = 81.4$ and $\sum (x - 50)^2 = 671.0$.
Worked solution & mark scheme
This 4-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Use the coded or uncoded variance formula with the given mean to start the variance calculation” …
- Full mark scheme, point by point
- Step-by-step worked solution
- Write your answer & get it marked instantly by AI