Fisher Exact Test Calculator
Calculates the two-sided Fisher exact p-value for a 2×2 table with fixed margins. The form displays two-sided fixed-margin hypergeometric probability beside fisher exact test, using a worked condition that can be recalculated with the labeled inputs.
Enter the statistical summaries
Fisher exact test
What fisher exact test answers
The fisher exact test page calculates the two-sided Fisher exact p-value for a 2×2 table with fixed margins.
Fisher exact test is limited to the statistical quantity named by the result panel. The fisher exact test calculation does not silently add a population, time horizon, causal direction, or decision threshold that is absent from the fields.
Before entering the fisher exact test data
- Cell a: For fisher exact test, the worked value for cell a is 8 counts. Treat the cell a entry (8 counts) explicitly as a count, proportion, rate, estimate, or model parameter before comparing fisher exact test conditions. The form enforces minimum 0.
- Cell b: For fisher exact test, the worked value for cell b is 2 counts. Treat the cell b entry (2 counts) explicitly as a count, proportion, rate, estimate, or model parameter before comparing fisher exact test conditions. The form enforces minimum 0.
- Cell c: For fisher exact test, the worked value for cell c is 1 counts. Treat the cell c entry (1 counts) explicitly as a count, proportion, rate, estimate, or model parameter before comparing fisher exact test conditions. The form enforces minimum 0.
- Cell d: For fisher exact test, the worked value for cell d is 5 counts. Treat the cell d entry (5 counts) explicitly as a count, proportion, rate, estimate, or model parameter before comparing fisher exact test conditions. The form enforces minimum 0.
The entries used for fisher exact test must refer to one coherent analysis condition. Combining incompatible populations, periods, or measurement definitions can produce valid fisher exact test arithmetic for a nonexistent study.
How fisher exact test is calculated
For fisher exact test, match every symbol in the relationship to a labeled field before substituting numbers. Fisher exact test is reported in the scale implied by the inputs and formula.
While checking fisher exact test, enter proportions on the scale expected by the labels; 0.40 and 40 are not interchangeable inputs for fisher exact test.
Worked values for fisher exact test
The default fisher exact test condition is Cell a = 8 counts, Cell b = 2 counts, Cell c = 1 counts, Cell d = 5 counts.
For the table 8,2 / 1,5, the two-sided exact p-value is approximately 0.035.
The live calculator reports Two-sided exact p-value 0.03496504 · Sample odds ratio 20. Repeating one intermediate step from two-sided fixed-margin hypergeometric probability provides a fixed fisher exact test reference check for later code changes.
Statistical context for fisher exact test
The two-sided definition sums tables no more probable than the observed table; software using another convention may differ slightly.
For fisher exact test, a p-value measures compatibility with a stated null model; it is not the probability that the null hypothesis is true and it does not measure practical importance.
A nearby method may answer the next question: chi square independence test.
When fisher exact test can mislead
When interpreting fisher exact test, pair the test result with the effect direction, effect size, uncertainty, sampling design, and the rule used for one-sided or two-sided inference.
As a second check for fisher exact test, confirm that Cell a and Cell d cover the same population and time boundary before interpreting the displayed probability or risk.
Mistakes to avoid in the fisher exact test setup
Before accepting fisher exact test, compare every entered value with its label, unit, and allowed domain after reading the printed relationship from left to right.
For fisher exact test, do not move a number between fields merely because the units look compatible; each label gives the number a different statistical role.
Another fisher exact test failure occurs when a rounded output is reused as though it were the original measurement. Carry guard digits through calculations that depend on fisher exact test, then round only the reported value.
Reporting fisher exact test reproducibly
Report fisher exact test using two-sided fixed-margin hypergeometric probability, followed by the entered values, units, exclusions, and analysis date. Name the fisher exact test population or dataset boundary instead of leaving it implicit.
Keep the full calculator output with the record, including Two-sided exact p-value 0.03496504 · Sample odds ratio 20. A later fisher exact test review can then distinguish a changed input from a different convention or software implementation.
Questions about fisher exact test
Does fisher exact test establish a causal or population conclusion?
No. The displayed fisher exact test value is conditional on the entered data and named method. The fisher exact test design, measurement process, and assumptions determine what can be concluded beyond those values.
How should fisher exact test be rounded?
Keep the unrounded fisher exact test for subsequent arithmetic, then report only the precision supported by the source measurements and the decision context. Extra digits in fisher exact test do not correct sampling or model error.
Which input deserves the closest boundary check?
For fisher exact test, start with cell d and then cell a. Confirm the fisher exact test units and allowed domain because a valid-looking entry can still describe the wrong statistical setup.