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T.TEST Function
Summary
The Excel T.TEST function calculates the probability associated with a Student's t-Test, helping you determine if two data sets are likely from populations with the same mean. Essential for statistical analysis and hypothesis testing in Excel.
Syntax
T.TEST(array1, array2, tails, type)Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
| array1 | Array |
Yes | First data set containing numeric values |
| array2 | Array |
Yes | Second data set containing numeric values |
| tails | Number |
Yes | Distribution tails: 1 (one-tailed) or 2 (two-tailed) |
| type | Number |
Yes | Test type: 1=Paired, 2=Equal variance, 3=Unequal variance |
Using the T.TEST Function
T.TEST is used in statistical analysis to compare means between two groups. Use it to test hypotheses about population means based on sample data. The function returns a p-value that indicates the probability that the observed difference occurred by chance.
Common T.TEST Examples
Paired Two-Tailed t-Test
=T.TEST(A2:A10,B2:B10,2,1)Calculates probability for paired t-test with two-tailed distribution using sample data from two groups. Result: 0.196016 indicates 19.6% probability difference is due to chance.
Two-Sample Equal Variance Test
=T.TEST(A1:A12,C1:C12,2,2)Performs two-sample t-test assuming equal variances (homoscedastic) with two-tailed distribution.
Frequently Asked Questions
Common Errors and Solutions
#N/A error
Cause: Different number of data points in array1 and array2 when type=1 (paired)
Solution: Ensure both arrays have identical count for paired tests
#VALUE! error
Cause: Tails or type arguments contain non-numeric values
Solution: Use only numbers for tails (1 or 2) and type (1, 2, or 3)
#NUM! error
Cause: Tails value other than 1 or 2
Solution: Tails must be exactly 1 (one-tailed) or 2 (two-tailed)
#VALUE! error
Cause: Array1 or array2 contains non-numeric data
Solution: Ensure all cells in both arrays contain numbers only
Notes
- T.TEST returns a non-negative t-statistic probability
- Two-tailed result (tails=2) is double the one-tailed result
- Available only in Excel 2007 and later versions
- Use Data Analysis ToolPak for more detailed t-test results with statistics
Compatibility
Available in: Excel 2007, Excel 2010, Excel 2013, Excel 2016, Excel 2019, Excel 2021, Microsoft 365
Not available in: Excel 2003 and earlier
Content last reviewed: December 9, 2025
Update frequency: As needed
Excel versions tested: Excel 2007+