Degrees of Freedom Calculator

Find degrees of freedom for one- or two-sample tests.

Degrees of freedom 29

Formula: One-sample: n - 1; two-sample: n1 + n2 - 2

Step-by-step with your numbers:

1. Values used:

2. Sample 1 size = 30

3. Sample 2 size (0 = one-sample) = 0

5. Degrees of freedom = 29

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Degrees of freedom count the independent pieces of information in an estimate.

The math behind it

A one-sample test has n - 1 df; a two-sample t-test has n1 + n2 - 2.

n1 30, one-sample gives df 29.

Why n - 1?

Estimating the mean uses up one degree of freedom.