Let L be the lower class boundary of a class in a frequency distribution and m be the midpoint of the class.
Question:
Let L be the lower class boundary of a class in a frequency distribution and m be the midpoint of the class. Which one of the following is the upper class boundary of the class?
(a) $m+\frac{(m+L)}{2}$
(b) $L+\frac{m+L}{2}$
(c) $2 m-L$
(d) $m-2 L$
Solution:
(c) 2m
Mid value $=\frac{\text { Lower limit+Upper limit }}{2}$
$\Rightarrow m=\frac{L+U}{2}$
$\Rightarrow U=2 m-L$
$\therefore$ Upper class boundary of the class $=2 m-L$