Explain, by taking a suitable example, how the arithmetic mean alters by subtracting a constant $k$ from each them.

To do:

We have to explain how the arithmetic mean alters by subtracting a constant $k$ from each them.

Solution:

We know that,

Mean $\overline{X}=\frac{Sum\ of\ the\ observations}{Number\ of\ observations}$

Let $x_1, x_2, x_3, x_4$ and $x_5$ be five numbers whose mean is $\overline{X}$.

This implies,

$\overline{X}=\frac{x_1+x_2+x_3+x_4+x_5}{5}$

A constant $k$ is subtracted from each term.

Therefore,

New mean $=\frac{\left(x_{1}-k\right)+\left(x_{2}-k\right)+\left(x_{3}-k\right)+\left(x_{4}-k\right)+\left(x_{5}-k\right)}{5}$

$=\frac{x_{1}+x_{2}+x_{3}+x_{4}+x_{5}-5 k}{5}$

$=\frac{x_{1}+x_{2}+x_{3}+x_{4}+x_{5}}{5}-k$

$=\bar{X}-k$ 

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Updated on: 10-Oct-2022

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