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Determine $\sum (x - \bar{x})^2$.
Mathematics 9709 · AS & A Level · Sampling and estimation
Sampling and estimation — practice question
The ages of 150 cars, measured in $x$ years, are summarised by $\sum x = 645$ and $\sum x^2 = 8287.5$. Find $\sum (x - \bar{x})^2$, where $\bar{x}$ represents the mean of $x$.
Worked solution & mark scheme
This 4-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Mean calculated correctly, $\bar{x}=4.3$ (or $645/150$ or $18.49$ seen)” …
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