TTEST function

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.

Important   This function has been replaced with one or more new functions that may provide improved accuracy and whose names better reflect their usage. This function is still available for compatibility with earlier versions of Excel. However, if backward compatibility is not required, you should consider using the new functions from now on, because they more accurately describe their functionality.

For more information about the new function, see T.TEST function.

Syntax

TTEST(array1,array2,tails,type)

The TTEST function syntax has the following arguments:

  • Array1     Required. The first data set.

  • Array2     Required. The second data set.

  • Tails     Required. 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     Required. 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.

  • TTEST uses the data in array1 and array2 to compute a non-negative t-statistic. If tails=1, TTEST returns the probability of a higher value of the t-statistic under the assumption that array1 and array2 are samples from populations with the same mean. The value returned by TTEST when tails=2 is double that returned when tails=1 and corresponds to the probability of a higher absolute value of the t-statistic under the “same population means” assumption.

Example

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

How do I copy an example?

  1. Select the example in this article.

    Important   Do not select the row or column headers.

    selecting an example from help

    Selecting an example from Help

  2. Press CTRL+C.

  3. In Excel, create a blank workbook or worksheet.

  4. In the worksheet, select cell A1, and press CTRL+V.

    Important   For the example to work properly, you must paste it into cell A1 of the worksheet.

  5. To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.

After you copy the example to a blank worksheet, you can adapt it to suit your needs.

1

2

3

4

5

6

7

8

9

10

11


12

A

B

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)

Applies To: Excel 2010, Excel Starter, Excel Online, SharePoint Online



Was this information helpful?

Yes No

How can we improve it?

255 characters remaining

To protect your privacy, please do not include contact information in your feedback. Review our privacy policy.

Thank you for your feedback!

Support resources

Change language