Question

The class marks of a frequency distribution are
26, 31, 36, 41, 46, 51.
Find the true class limits.

Answer 1

We have,
Class size = (31$-$26) = 5

Class mark = 26
Lower limit = $\left(26-\frac{5}{2}\right)=23.5$
Upper limit = $\left(26+\frac{5}{2}\right)=28.5$

Class mark = 31
Lower limit = $\left(31-\frac{5}{2}\right)=28.5$
Upper limit = $\left(31+\frac{5}{2}\right)=33.5$

Class mark = 36
Lower limit = $\left(36-\frac{5}{2}\right)=33.5$
Upper limit = $\left(36+\frac{5}{2}\right)=38.5$

Class mark = 41
Lower limit = $\left(41-\frac{5}{2}\right)=38.5$
Upper limit = $\left(41+\frac{5}{2}\right)=43.5$

Class mark = 46
Lower limit = $\left(46-\frac{5}{2}\right)=43.5$
Upper limit = $\left(46+\frac{5}{2}\right)=48.5$

Class mark = 51
Lower limit = $\left(51-\frac{5}{2}\right)=48.5$
Upper limit = $\left(51+\frac{5}{2}\right)=53.5$

Thus, the true class limits are 23.5, 28.5, 33.5, 38.5 , 43.5, 48.5, 53.5