Edit

WorksheetFunction.TTest method (Excel)

  • Article

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 the T_Test method.

Syntax

expression.TTest (Arg1, Arg2, Arg3, Arg4)

expression A variable that represents a WorksheetFunction object.

Parameters

Name Required/Optional Data type Description
Arg1 Required Variant Array1 - the first data set.
Arg2 Required Variant Array2 - the second data set.
Arg3 Required Double 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.
Arg4 Required Double Type - the kind of t-Test to perform.

Return value

Double

Remarks

The following table represents possible values for Arg4.

If type equals This test is performed
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 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.

Support and feedback

Have questions or feedback about Office VBA or this documentation? Please see Office VBA support and feedback for guidance about the ways you can receive support and provide feedback.