TTEST function

 from Microsoft Excel Help

 

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.

Syntax

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.

If type equals This test is performed
1 Paired
2 Two-sample equal variance (homoscedastic)
3 Two-sample unequal variance (heteroscedastic)

Remarks

  • 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 nonnumeric, TTEST returns the #VALUE! error value.

  • If tails is any value other than 1 or 2, TTEST returns the #NUM! error value.

     

Example

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

 

Ramsay's suggestion:

when in doubt use tails=1 and type=3

BACK TO Project 9