Question

The given table shows the marks obtained and the frequency. The cumulative frequency is ________

$$\begin{array}{cc}\text{Marks}& \text{Frequency}\\ 10-20& 4\\ 20-30& 9\\ 30-40& 6\\ 40-50& 10\end{array}$$

Answer 1

The cumulative frequency of a class interval is the sum of the frequencies of all classes upto that class including the frequency of that class.

Hence the cumulative frequency of the given data is

$$\begin{array}{ccc}\text{Marks}& \text{Frequency}& \text{Cumulative frequency}\\ 10-20& 4& \text{4}\\ 20-30& 9& \text{4 + 9 = 13}\\ 30-40& 6& \text{4 + 9 + 6= 19}\\ 40-50& 10& \text{4 + 9 + 6 + 10= 29}\end{array}$$