Question

Find the values of $p,q,r$ and $s$ in the given cumulative frequency distribution.

$\begin{array}{ccc}x& \text{frequency}& \text{Cumulative frequency}\\ 10& 3& p\\ 15& 10& q\\ 20& 25& r\\ 25& 7& s\\ 30& 5& 45+5=50\end{array}$

• A. $p=0,q=10,r=35,s=42$
• B. $p=3,q=13,r=28,s=35$
• C. $p=3,q=13,r=35,s=42$
• D. $p=3,q=13,r=38,s=45$

Answer 1

The correct option is D

$p=3,q=13,r=38,s=45$

As cumulative frequency is the sum of all previous frequencies up to the current point,

$\begin{array}{ccc}x& \text{frequency}& \text{Cumulative frequency}\\ 10& 3& p=3\\ 15& 10& q=10+3=13\\ 20& 25& r=13+25=38\\ 25& 7& s=38=7=45\\ 30& 5& 45+5=50\end{array}$