Question

Find the value of ∑f_ix_i $$\begin{array}{ccc}{x}_i& f_i& f_i{x}_i\\ 4& 10& A-........\\ 8& 11& B-........\\ 12& 9& C-.........\\ 16& 13& D-.........\\ & & \sum f_i{x}_i=..........\end{array}$$

• A. 40
• B. 88
• C. 444
• D. 208

Answer 1

The correct option is C 444

$1^{st}$ column is class marks list.
$2^{nd}$ column is frequencies.
The $3^{rd}$ column is the product of these 2 columns.

For first row,
class mark ($x_i$) = 4, frequency ($f_i$) = 10.
Product ($f_i{x}_i$) = 40.
Similarly the products for of other class marks can also be found.
$$\begin{array}{ccc}{x}_i& f_i& f_i{x}_i\\ 4& 10& 40\\ 8& 11& 88\\ 12& 9& 108\\ 16& 13& 208\end{array}$$

The sum of these products
($\sum f_i{x}_i$) = 40 + 88 + 108 + 208 = 444