# CI for StDve in Excel

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This topic contains 4 replies, has 2 voices, and was last updated by Örtlund 9 years, 7 months ago.

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- March 10, 2010 at 12:56 pm #53344

ÖrtlundParticipant@Exiguus**Include @Exiguus in your post and this person will**

be notified via email.Hello

Does anyone know the commando for calculating CI for StDve in excel?

0March 10, 2010 at 3:34 pm #189693

gbreaderParticipant@gbreader**Include @gbreader in your post and this person will**

be notified via email.Did you check out MS excel’s helpfile? This is what MS states…

The CONFIDENCE(alpha, sigma, n) function returns a value that you can use to construct a confidence interval for a population mean. The confidence interval is a range of values that are centered at a known sample mean. Observations in the sample are assumed to come from a normal distribution with known standard deviation, sigma, and the number of observations in the sample is n.

__SYNTAX__CONFIDENCE(alpha,sigma,n)

Parameters: Alpha is a probability and 0 < alpha < 1. Sigma is a positive number, and n is a positive integer that corresponds to the sample size.

Typically, alpha is a small probability, such as 0.05.

0March 10, 2010 at 8:25 pm #189696

ÖrtlundParticipant@Exiguus**Include @Exiguus in your post and this person will**

be notified via email.Yes, thats for the population mean,

What I am looking for if there is a comand/function to calculate CI for the StDev (sigma)?0March 10, 2010 at 8:41 pm #189698

gbreaderParticipant@gbreader**Include @gbreader in your post and this person will**

be notified via email.Found at http://www.graphpad.com/faq/viewfaq.cfm?faq=1381

__Computing the Ci of a SD with Excel__These Excel equations compute the confidence interval of a SD. N is sample size; alpha is 0.05 for 95% confidence, 0.01 for 99% confidence, etc.:

Lower limit: =SD*SQRT((N-1)/CHIINV((alpha/2), N-1))

Upper limit: =SD*SQRT((N-1)/CHIINV(1-(alpha/2), N-1))

0March 10, 2010 at 8:58 pm #189699

ÖrtlundParticipant@Exiguus**Include @Exiguus in your post and this person will**

be notified via email.Thanks a lot!

So there are probably non direct commands then?

O well, This will do the work also.

:)0 - AuthorPosts

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