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F distribution calculator

The F distribution calculator returns tail probabilities and critical values for F on a pair of numerator and denominator degrees of freedom.

What is F distribution calculator?

F is the ratio of two independent scaled chi-squares, which is why it is the reference distribution for ANOVA, for the overall test of a regression, and for comparing two variances.

An F table needs a separate page per α because it is indexed by two df values, which is why printed versions cover so few combinations. This evaluates any pair.

When should I use F distribution calculator?

  • Turning an ANOVA F statistic into a p-value.
  • Finding the critical value for a nested-model comparison.
  • Comparing two variances.

What data does it need?

Distribution parameters, plus a value x, a tail probability p, or both.

What does it report?

For x: the density or exact probability and each tail. For p: the lower, upper and two-tailed critical values.

What does it assume?

  • None — this evaluates a distribution rather than testing data against one.

See also