# Calculating p-value when tcalc, and df are given. Please help.

In a two-tailed t-test for means equality with df= 22, tcalc=3.511, and .001 < p<.01. How to calcultate exact p-value?

There was no table or anything else attached to this problem, and I can't find any examples in the book that would explain how to solve it when only this information is given. Please help.

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## 1 Answer

Use R or something similar as in

> 2 * pt(abs(3.511), df=22, lower.tail=FALSE)
[1] 0.001971369

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Could you please explain it? – juknee Feb 25 '14 at 23:58
Two-tailed (so double) the probability of being more extreme (so above) $3.511$ if there are $22$ degrees of freedom – Henry Feb 26 '14 at 0:07