Question

The standard deviation of the numbers 2, 4, 6, 8, 10, 12, 14, 16, 18,…

The standard deviation of the numbers 2, 4, 6, 8, 10, 12, 14, 16, 18, 20 is

NewBlackStudio Ai Solution

100% (3 rated)

Answer

The correct answer is: $\sqrt{33}\approx5.7446$

Explanation

We compute the population standard deviation of the ten numbers. First find the mean, then the sum of squared deviations, then the variance and square root.

Steps:

  1. Mean:

$$\bar{x}=\frac{2+4+6+\cdots+20}{10}=\frac{110}{10}=11$$

  1. Sum of squared deviations:

$$\sum_{i=1}^{10}(x_i-\bar{x})^2=81+49+25+9+1+1+9+25+49+81=330$$

  1. Variance (population):

$$\sigma^2=\frac{1}{10}\sum_{i=1}^{10}(x_i-\bar{x})^2=\frac{330}{10}=33$$

  1. Standard deviation:

$$\sigma=\sqrt{33}\approx5.7446$$

Therefore the standard deviation is $\sqrt{33}\approx5.7446$. (If you wanted the sample standard deviation, use denominator $n-1=9$, which gives $\sqrt{330/9}\approx6.0553$.)