(i)[2]
Calculate the mean age of all 32 club members.
(ii)[4]
Find the standard deviation of the ages of all 32 club members.
Mathematics 9709 · AS & A Level · Sampling and estimation
Sampling and estimation — practice question
The Quivers Archery club includes 12 Junior members and 20 Senior members. Among the Junior members, the mean age is $15.5$ years, and their standard deviation of age is $1.2$ years. The ages of the Senior members are summarised by $\Sigma y = 910$ and $\Sigma y^2 = 42\,850$, where $y$ stands for the age in years of a Senior member.
Worked solution & mark scheme
This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Correct method: divide the overall total age by the total number of people, for example $\frac{15.5\times12+910}{32}$” …
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