### TTEST(array1, array2, tails, type)

Returns the probability associated with a t test.

 array1 The first array. array2 The second array. tails The number of distribution tails:1 = one-tailed distribution2 = two-tailed distribution type The kind of t-Test to perform:1 = paired2 = two sample equal variance (homoscedastic)3 = two sample unequal variance (heteroscedastic)

#### Remarks

 * T.TEST was added in Excel 2010 to replace this function.* You can use this function to determine whether two samples are likely to have come from the same two underlying populations that have the same mean.* If "array1" and "array2" have a different number of data points, and type = 1 (paired), then #N/A is returned.* If "tails" is not an integer, it is truncated.* If "tails" < 1, then #NUM! is returned.* If "tails" > 1, then #NUM! is returned.* If "tails" is not numeric, then #VALUE! is returned.* If "type" is not an integer, it is truncated.* if "type" < 1, then #NUM! is returned.* If "type" > 3, then #NUM! is returned.* If "type" is not numeric, then #VALUE! is returned.* For the Microsoft documentation refer to support.microsoft.com

 A 1 =TTEST({3,4,5,8,9,1,2,4,5},{6,19,3,2,14,4,5,17,1},2,1) = 0.196 2 =TTEST({1,2,3,4,5},{1,2,3,4,5},2,1) = #DIV/0!