Excel Formula for t Test

Better instructions will be placed here at a later date. For now, here are some from the Excel Help menu.

t test

Returns the probability associated with a Student’s t-Test. Use TTEST to determine whether two samples are likely to have come from the same two underlying populations that have the same mean.


TTEST(array1, array2, tails, type)

  • Array1 is the first data set.
  • Array2 is the second data set.
  • Tails specifies the number of distribution tails. If tails = 1, TTEST uses the one-tailed distribution. If tails = 2, TTEST uses the two-tailed distribution.
  • Type is the kind of t-test to perform.
    1 – Paired
    2 – Two-sample equal variance (homoscedastic)
    3 – Two-sample unequal variance (heteroscedastic)


  • If array1 and array2 have a different number of data points, and type = 1 (paired), TTEST returns the #N/A error value.
  • The tails and type arguments are truncated to integers.
  • If tails or type is non-numeric, TTEST returns the #VALUE! error value.
  • If tails is any value other than 1 or 2, TTEST returns the #NUM! error value.


TTEST({3,4,5,8,9,1,2,4,5},{6,19,3,2,14,4,5,17,1},2,1) equals 0.196016

I created an Excel spreadsheet that contains all of the necessary formulas.