Related Function:

The T.TEST function returns the probability associated with the Student’s T Test, which is commonly used for identifying whether two data sets are likely to have come from the same two underlying populations with the same mean.

  • This function was introduced in Excel 2010 and so is not available in earlier versions.
  • The T.TEST function replaces the TTEST function included in earlier versions of Excel.




Argument Description
array1 The first data set
array2 The second data set – must have the same length as array1
tails The number of tails for the distribution. This can be either:

  1 Uses the one-tailed distribution
  2 Uses the two-tailed distribution
type An integer that represents the type of t-test. This can be either:

  1 Paired T-Test
  2 Two-sample equal variance T-Test
  3 Two-sample unequal variance T-Test


  A B C D
1 Data 1 Data 2    
2 12 15    
3 17 18    
4 14 27    
5 13 16    
6 5 28    
8 Formula Result Notes
9 =T.TEST(A2:A6,B2,B6,1,1) 0.053977 Probability associated with a Student’s paired t-Test, with a one-tailed distribution
10 =T.TEST(A2:A6,B2,B6,2,1) 0.107954 Probability associated with a Student’s paired t-Test, with a two-tailed distribution

Common Function Error(s)

Problem What went wrong
#VALUE! Occurs if either the tails argument or the type argument is non-numeric
#NUM! Occurs if either:

  the supplied tails argument has any value other than 1 or 2
  the supplied type argument is not equal to 1, 2 or 3
#N/A Occurs if the two supplied arrays have different lengths