How to Find a P-Value on a TI-84

A p-value doesn’t get calculated on its own — it’s always the output of running a specific hypothesis test, not a standalone formula you plug numbers into. On a TI-84, that means going through STAT → TESTS and picking the test that matches your data, not hunting for a dedicated “p-value” function.

What it means

The p-value is the probability of seeing a result at least as extreme as yours if the null hypothesis were actually true. A small p-value (conventionally below 0.05) means your data would be unlikely under the null hypothesis, which is the usual threshold for rejecting it. A large p-value means your data is quite plausible under the null hypothesis, giving you no reason to reject it.

Worked example: 1-sample Z-Test

Testing whether a sample mean of x̄ = 106 (n = 40, known σ = 15) is significantly different from a hypothesized population mean of μ₀ = 100: running a 1-Sample Z-Test with those inputs produces both a z-statistic and its corresponding p-value directly — no separate lookup table needed, since the calculator computes the exact tail probability itself.

Try it yourself

Go to Tools → Tests on the TI-84 Calculator and pick the test that matches your situation — 1-Sample Z, 1-Sample T, 2-Sample T, 1-Prop Z, 2-Prop Z, or a χ² test. Enter the values it asks for and press the test button; the p-value comes back alongside the test statistic in the result panel, exactly like the real calculator’s STAT TESTS output.