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Question:
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The variance of the following data is
$$
\begin{array}{cccccccc}
x_i & 6 & 10 & 14 & 18 & 24 & 28 & 30 \\
f_i & 2 & 4 & 7 & 12 & 8 & 4 & 3
\end{array}
$$
Options:
$$
\begin{array}{cccccccc}
x_i & 6 & 10 & 14 & 18 & 24 & 28 & 30 \\
f_i & 2 & 4 & 7 & 12 & 8 & 4 & 3
\end{array}
$$
Solution:
1602 Upvotes
Verified Answer
The correct answer is:
43.4
$\begin{aligned} & \text { Now, variance }=\frac{\sum f_i d_i^2}{N}-\left(\frac{\sum f_i d_i}{N}\right)^2 \\ & =\frac{1}{40} \times 1776-1=\frac{1736}{40}=43.4\end{aligned}$
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