(i)[2]
Find the mean height of the 27 people left in the group.
(ii)[4]
Determine $\Sigma x^2$ for the original group of 28 people. Hence determine the standard deviation of the heights of the remaining group of 27 people.
Mathematics 9709 · AS & A Level · Sampling and estimation
Sampling and estimation — practice question
The heights, $x$ cm, of a set of 28 people were recorded. The mean height was 172.6 cm and the standard deviation was 4.58 cm. One person with height 161.8 cm then left the group.