Question

Calculate the sample standard deviation and sample variance of the sample data shown, to two decimal places

x
28.9
29.6
4.7
28.5
14.3
6.9
4.9
19.9

Sample standard deviation: ?

Sample variance :?

Answer 1

$Sample~mean=\bar{x}=\frac{1}{8}\sum_{i=1} ^8x_i=17.21\\ Sample~variance=\frac{1}{7}\sum_{i=1}^8(x_i-\bar{x})^2=\frac{1}{7}\left(\sum x_i^2-8\bar{x}^2 \right )=121.10\\ Sample~standard~deviation=\sqrt{Sample~variance}=11.00$