# Standard deviation

• May 28th 2009, 07:10 AM
Peikko
Standard deviation
I was wondering if there is anyway to calculate standard deviation when you have the Mean and the N values.

For example:

Mean = 7.01
n = 91
• May 28th 2009, 07:43 AM
artvandalay11
if you are just told that you have a distribution with mean=m and it is of size n, you cannot figure out the standard deviation
• May 28th 2009, 09:35 AM
Peikko
Thanx for the reply. Is there any other way to get around it as I need to get SD from data that shows people in trial (91 ) and their % blood levels ( 7.01 ) ?
• May 28th 2009, 10:58 AM
artvandalay11
Well if you actually have the data you can compute it with the formula for standard deviation... but if you just have two numbers written down of n=91 and mean=7.01 I don't think there is any way for you to get the standard deviation
• May 30th 2009, 06:40 AM
mr fantastic
Quote:

Originally Posted by Peikko
Thanx for the reply. Is there any other way to get around it as I need to get SD from data that shows people in trial (91 ) and their % blood levels ( 7.01 ) ?

You have already been told by reputable members both here and at at least one other website that this cannot be done. Thread closed.