Degrees of Freedom Calculator
Calculate df for common statistical tests.
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Select the test type, then enter the required parameters (sample sizes, number of categories, etc.). The calculator outputs the degrees of freedom with an explanation of the formula used.
About This Calculator
Degrees of freedom (df) represent the number of independent values that are free to vary in a calculation. They are essential for determining critical values and p-values from t, chi-square, and F distributions. The df depends on the specific test and the sample size.
Frequently Asked Questions
Why are degrees of freedom important?
They determine the shape of the t, chi-square, and F distributions used to calculate p-values. Using the wrong df gives incorrect p-values and can lead to wrong conclusions.
What is the df for a one-sample t-test?
For a one-sample t-test, df = n - 1, where n is the sample size.
How does Welch's df work?
Welch's approximation for unequal variances uses a complex formula that accounts for both sample sizes and variances, often producing a non-integer df.