Question

Find the value of $\sum f_i{x}_i$ from the given table.

$\begin{array}{cc}{x}_i& f_i\\ 4& 10\\ 8& 11\\ 12& 9\\ 16& 13\end{array}$

Answer 1

$\begin{array}{ccc}{x}_i& f_i& f_i{x}_i\\ 4& 10& 40\\ 8& 11& 88\\ 12& 9& 108\\ 16& 13& 208\\ & & \sum f_i{x}_i\end{array}\Rightarrow \sum f_i{x}_i=(40+88+108+208)\Rightarrow \sum f_i{x}_i=444$
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