Question

Find the cumulative frequency for the class interval 65-70$\begin{array}{cc}\text{Class interval}& \text{Frequency}\\ 50-55& 5\\ 55-60& 20\\ 60-65& 10\\ 65-70& 10\\ 70-75& 9\\ 75-80& 6\\ 80-85& 6\\ 85-90& 8\end{array}$

• A. True
• B. False
• C. 15
  
• D. 25

Answer 1

The correct option is B

False

Cumulative frequency of a class interval is the sum of the frequencies of all the classes up to this class interval

Hence for the given table the cumulative frequency is as follows

$\begin{array}{ccc}\text{Class interval}& \text{Cumulative Frequency \& C.f}& \\ 50-55& 5& 5\\ 55-60& 20+5=25& 25\\ 60-65& 20+5+10=35& 35\\ 65-70& 20+5+10+10=45& 45\\ 70-75& 20+5+10+10+9=54& 54\\ 75-80& 20+5+10+10+9+6=60& 60\\ 80-85& 20+5+10+10+9+6+6=66& 66\\ 85-90& 20+5+10+10+9+6+6+8=74& 74\end{array}$