Answer question number 8

Dear Student,
If we convert the above given series from cummulative to normal class intervals, then we will get,

Class Interval	Frequency	Cummulative Frequence
161-162	2	2
162-163	6	8
163-164	11	19
164-165	13	32
165-166	13	45
166-167	13	58
167-168	27	85
168-169	8	93
169-170	7	100

Range is difference between the lower limit of the minimum interval and upper limit of the maximum interval of the grouped data
Range= 170-161
=9
Coefficent of range
 $$\begin{gathered} =\frac{Highest-lowest}{Highest+lowest} \\ =\frac{170-161}{170+161} \\ =\frac{9}{331} \end{gathered}$$
=0.027 or 0.03

Regards