The standard deviation of the numbers 22, $26,28,20,24,30$ is

The standard deviation of the numbers 22, $26,28,20,24,30$ is
  1. 2
  2. 2.4
  3. 3.24
  4. 3.42

Solution

Given numbers 22, 26, 28, 20, 24, 30 $ \bar{x}=\frac{22+26+28+20+24+30}{6}=\frac{150}{6}=25 $ Now, $\left(x_i-\bar{x}\right)^2$ is $9,1,9,25,1,25$ $ \begin{aligned} & \text { Now, } S D=\sqrt{\frac{\Sigma\left(x_i-\bar{x}\right)^2}{n}} \\ & =\sqrt{\frac{9+1+9+25+1+25}{6}}=\sqrt{\frac{70}{6}}=3.42 \end{aligned} $

Asked in: AP EAMCET 2018 (23 Apr Shift 1)

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