The Excel TTEST function returns the probability (p–value) of a Student's t–test on two data sets. It is a legacy name — Microsoft now recommends T.TEST, which is identical.
Syntax
| Argument | Description | |
|---|---|---|
array1 | Required | The first data set. |
array2 | Required | The second data set. |
tails | Required | 1 = one-tailed, 2 = two-tailed. |
type | Required | 1 = paired; 2 = two-sample equal variance; 3 = two-sample unequal variance. |
How to use it
TTEST compares two samples and returns the p–value — the probability that the difference in means arose by chance. Choose the tail count and the test type.
type 1 is a paired test (the two arrays must be the same length); type 2 assumes equal variances; type 3 (Welch) does not. A small p–value (say below 0.05) suggests the means differ significantly.
Use the modern name: =T.TEST(array1, array2, tails, type) takes the same four arguments and returns the same p–value. TTEST is kept only for backward compatibility.
Try it: interactive demo
Pick a TTEST example to see the formula and its result.
Practice workbook
Frequently asked questions
Is TTEST the same as T.TEST?
T.TEST (Excel 2010+) takes the same array1, array2, tails, and type arguments and returns identical p–values. TTEST is kept for backward compatibility.What do the type values mean?
How do I read the result?
Should I switch to T.TEST?
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