# Math Help - standard deviation and mean deviation

1. ## standard deviation and mean deviation

Q::it Is Asked To Show That The Standard Deviation For Normal Distribution Is Approximately 25% More Than The Mean Deviation

I Have Absolutely No Idea As To Proceed
Can I Have A Descriptive Solution

2. Originally Posted by pawan6719
Q::it Is Asked To Show That The Standard Deviation For Normal Distribution Is Approximately 25% More Than The Mean Deviation

I Have Absolutely No Idea As To Proceed
Can I Have A Descriptive Solution
You need to work with the standard normal distribution, and so show that:

$\frac{1}{\sqrt{2\pi}} \int_{-\infty}^{\infty} |x|e^{-x^2/2}~dx \approx 1.25$

RonL