TTEST

See Also

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

The example may be easier to understand if you copy it to a blank spreadsheet.

How?

Create a blank spreadsheet.
Select the example in the Help topic.

Selecting an example from Help
Press CTRL+C.
In the spreadsheet, select cell A1, and press CTRL+V.
To switch between viewing the formula that returns the result and the result in the cell, select the cell and press F2 and then ENTER, or click Commands and Options on the spreadsheet toolbar, click the Formula tab, and look in the Formula in active cell (active cell) box.

Data 1	Data 2
3	6
4	19
5	3
8	2
9	14
1	4
2	5
4	17
5	1
Formula	Description (Result)
=TTEST(A2:A10,B2:B10,2,1)	Probability associated with a Student's paired t-Test, with a two-tailed distribution (0.196016)