Question

What is the class mark of the class $135-155$?

Answer 1

$\Rightarrow$ Class interval $=135-155$

Lower class limit $=135$ and Upper class limit $=155$

$\Rightarrow$ $Classmark=\frac{Lowerclasslimit+Upperclasslimit}{2}$

$=\frac{135+155}{2}$

$=\frac{290}{2}$

$=145$

$\therefore$ Class mark of class $135-155$ is $145$