How to determine statistical significance using T-Test in Excel?

I have two groups of data sets, A and B. I would like to know weither the ave开发者_开发技巧rage value of A significantly differs then B's average. How to do that in Excel 2007?

(I know there's a TTEST formula in excel, I also know I don't need to use the paired version of it, what other parameters do I need to set and how to interpert the result?)

Thanks,

Jon

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=ttest(array1,array2,tails,type)

array1 is data set A

array2 is data set B

tails: 1= one tailed, 2 = two tailed. Use one tailed if you are testing whether A is higher than B, or whether A is lower than B. Use two tailed if you are testing whether A is either higher or lower than B. (Probably 1 for your situation.)

type: You said you don't need paired, which is Type 1. Type 2 is if your data sets have equal variance, and Type 3 is if they have unequal variance. For example if the data points in A are all pretty close, but in B they are wildly different, use Type 3.