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TTEST Function
Summary
The TTEST function calculates the probability value associated with a Student's t-Test, helping you determine if two data sets are likely from populations with identical means. This statistical tool is essential for hypothesis testing in data analysis.
Syntax
TTEST(array1, array2, tails, type)Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
| array1 | Array |
Yes | First dataset containing numeric values for comparison |
| array2 | Array |
Yes | Second dataset containing numeric values for comparison |
| tails | Number |
Yes | Distribution tails (1 for one-tailed, 2 for two-tailed) |
| type | Number |
Yes | Test type: 1=Paired, 2=Equal variance, 3=Unequal variance |
Using the TTEST Function
TTEST is a powerful statistical function for comparing means between two groups. Use it to test hypotheses about population means using sample data from experiments, surveys, or A/B testing scenarios. Ideal for researchers, analysts, and quality control professionals.
Common TTEST Examples
Paired Two-Tailed Test
=TTEST(A2:A10,B2:B10,2,1)Calculates probability for paired t-test using two-tailed distribution on sample datasets in A2:A10 and B2:B10 (result: 0.19602)
Two-Sample Equal Variance
=TTEST(C1:C10,D1:D10,2,2)Performs two-sample t-test assuming equal variances with two-tailed distribution
One-Tailed Unequal Variance
=TTEST(E1:E8,F1:F8,1,3)One-tailed test for datasets with unequal variances (heteroscedastic)
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 paired arrays have identical lengths or use type 2/3
#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: Set tails to 1 (one-tailed) or 2 (two-tailed)
#DIV/0! Error
Cause: One or both arrays contain no variance (all identical values)
Solution: Verify datasets have variation or use different data
Notes
- Deprecated function - consider T.TEST for new workbooks
- Returns p-value (lower values indicate greater significance)
- Requires equal array lengths for paired tests (type=1)
- Truncates tails/type to integers automatically
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+