Question

Let $\mathrm{m}$ be the mid-point and $\mathrm{l}$be the upper class limit of a class in a continuous frequency distribution. The lower class limit of the class is:

• A. $2\mathrm{m}+\mathrm{l}$
• B. $2\mathrm{m}-\mathrm{l}$
• C. $\mathrm{m}-\mathrm{l}$
• D. $\mathrm{m}-2\mathrm{l}$

Answer 1

The correct option is B

$2\mathrm{m}-\mathrm{l}$

Explanation of correct option:

Given, upper limit$=\mathrm{l}$ and midpoint $=\mathrm{m}$

We know that,

$$\begin{gathered} \mathbf{Mid}\mathbf{}\mathbf{point}\mathbf{=}\mathbf{}\frac{\mathbf{Upper}\mathbf{}\mathbf{limit}\mathbf{}\mathbf{+}\mathbf{}\mathbf{Lower}\mathbf{}\mathbf{limit}}{\mathbf{2}} \\ \Rightarrow \mathrm{m}=\frac{\mathrm{l}+\mathrm{Lower}\mathrm{limit}}{2} \\ \Rightarrow \mathrm{Lower}\mathrm{limit}=2\mathrm{m}-\mathrm{l} \end{gathered}$$

Hence, option(B) is correct.