# New Home Edition User Confused by Variance result.

Posted 10 years ago
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 Calculate the Mean and StandardDeviation of a list: 140,120,100,80,60.  Okay the answers should be - mean = 100, standard deviation = 28.28, variance = 800. I can't understand why Mathematica says the standard deviation is 31.6228 and the variance is 1000. The formula for variance  in the documentation is the same  as my spreadsheet formula, I can't understand why the result is different. Please help out a new user and tell me where I am going wrong.list1={140,120,100,80,60}Mean[list1]N[StandardDeviation[list1]]N[Variance[list1]]
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Posted 10 years ago
 Thank you for your reply. Okay, the number of observations used to figure the variance is N-1. I feel funny about not seeing that before, like not realizing my t-shirt is on backwards.
Posted 10 years ago
 In this case, 800 is the biased sample variance. As documented, the function Variance uses Bessel's correction and returns the unbiased sample variance, 1000.