Question

The following frequency distribution gives the monthly consumption of electricity of 68 consumers of a locality.
Find the median of the data.

$\begin{array}{cc}\text{Monthly consumption (in units)}& \text{Numbers of customers}\\ 65-85& 4\\ 85-105& 5\\ 105-125& 13\\ 125-145& 20\\ 145-165& 14\\ 165-185& 8\\ 185-205& 4\end{array}$

• A. 140
• B. 147
• C. 137
• D. 132

Answer 1

The correct option is C

137

$\begin{array}{ccc}\text{Class interval}& \text{Frequency}& C.F\\ 65-85& 4& 4\\ 85-105& 5& 9\\ 105-125& 13& 22\\ 125-145& 20& 42\\ 145-165& 14& 56\\ 165-185& 8& 64\\ 185-205& 4& 68\end{array}$

Here, n = 68 and hence $\frac{n}{2}=34$
So, median class is 125-145

When we See the 34th Observation and join it to the ogive from both x and y axis,

The Median which we See from graph is 137.