Syntax
TTEST(array1, array2, tails, type)
| Parameter | Description |
|---|---|
| array1 | Parameter of the TTEST function. |
| array2 | Parameter of the TTEST function. |
| tails | Parameter of the TTEST function. |
| type | Parameter of the TTEST function. |
Examples
Compare two product ratings
Formula
=TTEST(A2:A50, B2:B50, 2, 3)
Returns the two-tailed p-value comparing product ratings in columns A and B using Welch's t-test. A low p-value indicates the products have significantly different ratings.
Paired diet study
Formula
=TTEST(C2:C16, D2:D16, 1, 1)
Returns the one-tailed p-value for a paired test comparing weight before and after a diet for 15 subjects. Tails=1 tests specifically if the diet reduced weight.
Manufacturing comparison
Formula
=TTEST(E2:E101, F2:F101, 2, 2)
Returns the p-value comparing output measurements from two production lines with assumed equal variance.
Common Errors
#N/A
Paired tests (type 1) require arrays of equal length.
#NUM!
Tails must be 1 or 2, type must be 1, 2, or 3.
Tips
Use T.TEST instead
TTEST is the compatibility version. T.TEST is the modern replacement with identical behavior and consistent naming.
Blank cells and text are ignored
Non-numeric cells in the arrays are excluded from the calculation. Make sure your data ranges do not inadvertently include headers or text notes.
Sample size matters
T-tests become more reliable with larger samples. With very small samples (n < 5 per group), results should be interpreted cautiously.
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