## Excel Office

Excel How Tos, Tutorials, Tips & Tricks, Shortcuts

# What is T.TEST function in Excel?

T.TEST function is one of Statistical functions in Microsoft Excel that returns the probability associated with a Student’s t-Test. Use T.TEST to determine whether two samples are likely to have come from the same two underlying populations that have the same mean.

## Syntax of T.TEST function

T.TEST(array1,array2,tails,type)

The T.TEST function syntax has the following arguments:

• Array1:  The first data set.
• Array2: The second data set.
• Tails: Specifies the number of distribution tails. If tails = 1, T.TEST uses the one-tailed distribution. If tails = 2, T.TEST uses the two-tailed distribution.
• Type:  The kind of t-Test to perform.

## Parameters

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

## Explanation of T.TEST function

• If array1 and array2 have a different number of data points, and type = 1 (paired), T.TEST returns the #N/A error value.
• The tails and type arguments are truncated to integers.
• If tails or type is nonnumeric, T.TEST returns the #VALUE! error value.
• If tails is any value other than 1 or 2, T.TEST returns the #NUM! error value.
• T.TEST uses the data in array1 and array2 to compute a non-negative t-statistic. If tails=1, T.TEST 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 T.TEST 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 of T.TEST function

Steps to follow:

1. Open a new Excel worksheet.

2. Copy data in the following table below and paste it in cell A1

Note: For formulas to show results, select them, press F2 key on your keyboard and then press Enter.

You can adjust the column widths to see all the data, if need be.

 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 =T.TEST(A2:A10,B2:B10,2,1) Probability associated with a Student’s paired t-Test, with a two-tailed distribution. 0.196016