Question 6
For the following distribution,
$\begin{array}{cccccc}Class& 0-5& 5-10& 10-15& 15-20& 20-25\\ Frequency& 10& 15& 12& 20& 9\end{array}$
the sum of lower limits of the median class and modal class is
(a) 15
(b) 25
(c) 30
(d) 35

Here,
$\begin{array}{ccc}Class& Frequency& Cumulative\\ & & frequency\\ 0-5& 10& 10\\ 5-10& 15& 25\\ 10-15& 12& 37\\ 15-20& 20& 57\\ 20-25& 9& 66\end{array}$
Now, $\frac{N}{2}=\frac{66}{2}=33$, which lies in the interval 10-15. Therefore, lower limit of the median class is 10.
The highest frequency is 20, which lies in the interval 15-20. Therefore, lower limit of modal class is 15.
Hence, sum of lower limits is 10+15=25.