Question

Please help me to find this out..

Answer 1

The standard deviation is defined as the square root of the variance:

$\displaystyle \text{Variance: } \sigma^2 = \sum_{i=1}^N \dfrac{(x_i-\mu)^2}{N}$

$\displaystyle \text{Standard deviation: } \sigma = \sqrt{\sum_{i=1}^N \dfrac{(x_i-\mu)^2}{N}}$