Question

Find the values of p, q, r and s in the given cumulative frequency distribution.
$\begin{array}{ccc}DataPoint& \text{frequency}& \text{Cumulative frequency}\\ 10& 3& p=----\\ 15& 10& q=----\\ 20& 25& r=----\\ 25& 7& s=----\\ 30& 5& 50\end{array}$

• 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 the cumulative frequency for a certain class interval of a frequency table is the progressive sum of the frequencies from either the first or last class to that particular class.

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