Question

$\sum f_i$ and $\sum f_i{x}_i$ of the given data are respectively_____ and ______.
$\begin{array}{cc}\text{Number of runs}\left(x_i\right)& \text{Tally marks}\\ 1& |||\\ 2& ||||||\\ 4& |\\ 6& ||||\end{array}$

• A. 20, 50
• B. 15, 45
• C. 10, 25
• D. 45, 15

Answer 1

The correct option is B 15, 45

$\begin{array}{cccc}\text{Number of runs}\left(x_i\right)& \text{Tally marks}& \text{Frequency}\left(f_i\right)& f_i{x}_i\\ 1& |||& 3& 3\\ 2& ||||||& 7& 14\\ 4& |& 1& 4\\ 6& ||||& 4& 24\end{array}$
$\therefore$ $\sum f_i$= 3+ 7 + 1 + 4 =15.

and $\sum f_i{x}_i$ = 3 +14 +4 +24 = 45.