How to use the ancova calculator
Prepare the values for this calculation
Fit a one-way ANCOVA with one numeric covariate and a common covariate slope across groups. Use the formula below to check that it answers your question. Read the input units before transferring figures from a statement, measurement or dataset.
Enter and check each input
- group,covariate,outcome — one observation per line: keep one record per line and preserve the column order shown in the example. Replace the example data with your own complete dataset.
The input table gives a complete example. Keep units and time periods consistent across related fields.
Calculate and resolve any input error
Choose Calculate after entering the values. Changes also update the answer after a short pause. If an error appears, follow its message, correct the field and calculate again. Reset restores the example values.
Interpret the answer
Check ANCOVA group-effect p-value first. With the unchanged example inputs, it is 0.000090434511. Compare the additional metrics with the primary result; each has its own label and unit.
Compare and keep a useful result
The result diagram shows the inputs, method and output. A numeric chart is shown only when the calculation supports a meaningful numeric relationship.
Use Copy result or Download CSV to keep the answer. Share tool shares the page address without placing your input values in the URL. Recheck inputs and assumptions before using the result for a decision.
ANCOVA Calculator formula
Compare y=β₀+β₁x+group effects with the reduced model y=β₀+β₁x. The group F test uses the reduction in SSE over g−1 df and the full-model residual MSE.
Inputs and units
| Input | Format / range | Example |
|---|---|---|
| group,covariate,outcome — one observation per line | One row per line | A,1,5
A,2,6
A,3,7
B,1,7
B,2,8
B,3,9
C,1,8
C,2,10
C,3,11 |
Worked example
Using the example inputs above, the ancova group-effect p-value is 0.000090434511.
- ANCOVA group-effect p-value
- 0.000090434511
- F statistic
- 101.111111111111
- Group df
- 2
- Residual df
- 5
- Common covariate slope
- 1.166666666667
- Overall covariate mean
- 2
Results and assumptions
One-way ANCOVA with a common covariate slope. This model assumes linear covariate effects and homogeneous slopes across groups.
Fix an input or unexpected result
If your answer differs from the example, choose Reset and compare every field, including selected units and options. Check percentage versus decimal entry and whether values describe the same period. Round only the final displayed answer when reproducing the formula.
If a discrepancy remains, report the calculator issue with the page address, non-sensitive example inputs, actual result, expected result and a reference for your calculation.