Question

The class marks of a frequency distribution are given as follow 15,20,25,...
The class corresponding to the class mark 20 is

• A. $12.5-17.5$
• B. $17.5-22.5$
• C. $18.5-21.5$
• D. $19.5-20.5$

Answer 1

The correct option is B $17.5-22.5$

Width=5

Class marks=20

$\therefore Lowerlimit=20-\frac{5}{2}$

$\Rightarrow \frac{40-5}{2}=\frac{35}{2}=17.5$

$Upperlimit=20+\frac{5}{2}$

$\Rightarrow \frac{40+5}{2}=\frac{45}{2}=22.5$

Hence the class corresponding to the class mark 20 is $17.5-\mathrm{22.5.}$