In Google Sheets, the T.TEST function is used to perform a t-test on two sets of data to determine if there is a significant difference between their means.

It is commonly used in statistical analysis to compare the means of two samples and evaluate the likelihood that the difference observed between them is due to chance.

The syntax for the T.TEST function in Google Sheets is as follows:

T.TEST(range1, range2, tails, type)

range1 and range2 are the two ranges or arrays of data that you want to compare.

tails is an optional argument that specifies the number of tails for the t-test. It can be either 1 or 2, representing a one-tailed or two-tailed test, respectively.

By default, it is set to 2 if not provided.type is an optional argument that specifies the type of t-test to perform. It can be either 1 (paired t-test) or 2 (unpaired t-test).

If not specified, an unpaired t-test is performed by default.

The T.TEST function returns the probability associated with the t-test. If you set tails to 2, the function will return the probability of observing a difference as extreme as the one calculated, assuming the null hypothesis (no difference) is true. If you set tails to 1, it will return the probability for a one-tailed test.

Here's an example usage of the T.TEST function:

=T.TEST(A1:A10, B1:B10, 2, 2)

This would perform a two-tailed unpaired t-test on the ranges A1:A10 and B1:B10 using the Student's t-distribution and return the probability of observing the difference in means under the assumption of no difference.