# Standard Deviation-What?

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I cannot figure out how to do standard deviation. standard deviation 2, 5, 47, 11, 13, 48, 39, 36

2-25.125=-23.125 = 534.77
5-25.125=-20.125 = 405.02
47-25.125=21.875 = 478.52
11-25.125=-14.125 = 199.52
13-25.125=-12.125 = 147.02
48-25.125=22.875 = 523.27
39-25.125=13.875 = 192.52
36-25.125=10.875 = 118.27
Sum 2598.41

If I divide by one less,which I am supposed to do I think, I get 371.20 sqrt= 19.27
If I divide by 8 I get 324.80 sqrt=18.02

The possible answers are: A) 24.5 B) 324.9 C) 18 D) 25.1

• Standard Deviation-What? -

I checked all your calculations and found no errors.
(although you wrote your solutions with incorrect use of the "equal' sign)

Here is a webpage, by Wolfram a dependable source,
which explains the difference in the two methods of finding standard deviation.
Check with your text or your instructor whether you divide by N or N-1 .

I also got 19.27 after dividing by 7 and
18.02 after dividing by 8, so I don't know where they get your answers.

• Standard Deviation-What? -

oops
forgot to post the webpage.

http://mathworld.wolfram.com/StandardDeviation.html

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