calculated SD vs Data Analysis

[robertdseals]

Hello,
When I calculate the standard deviation for a set of numbers, I get a different amount then when I use the "Data Analysis" on the data tab. Why is that? For instance, when I calculate the SD for 1, 2, 3, 4, 5, 6 I get 1.707825 but the data analysis gives me 1.870828. This is significantly different.
Which is correct?

 

[JoeMo]

Possibly, your data analysis is using STDEV:
STDEV uses the following formula:

where x is the sample mean AVERAGE(number1,number2,…) and n is the sample size.

and your Excel formula is using STDEV.P:

STDEV.P uses the following formula:

where x is the sample mean AVERAGE(number1,number2,…) and n is the sample size.

Notice that the two are virtually identical for very large samples n --> infinity, but significantly different for your n = 6 sample.

 

[robertdseals]

Excellent! Thanks,