The Excel T.TEST function calculates the probability associated with the Student's T Test, which is commonly used for identifying whether two data sets are likely to have come from the same two underlying populations with the same mean.
The T.TEST function is new to Excel 2010. However, this is simply a renamed version of the TTEST function, that is available in earlier versions of Excel.
The format of the T.Test function is :
where the function arguments are:
|array1||-||The first data set|
|array2||-||The second data set (must have the same length as array1)|
|tails||-||The number of tails for the distribution. This can be either :|
|type||-||An integer that represents the type of t-test. This can be either :|
Note that the probability associated with the two-tailed T-Test is double that of the one-tailed T-Test.
Further information and examples of the Excel T.Test function are provided on the Microsoft Office website.
If you get an error from the Excel T.Test Function, this is likely to be one of the following :
|#N/A||-||Occurs if the two supplied arrays have different lengths|
|#VALUE!||-||Occurs if either the tails argument or the type argument is non-numeric|