Two Proportion Test Power Calculator
Estimates approximate power for comparing two independent proportions. The form displays approximate normal power beside two proportion test power, using a worked condition that can be recalculated with the labeled inputs.
Set the labeled inputs
Two Proportion Test Power
Scope of the two proportion test power method
The two proportion test power page estimates approximate power for comparing two independent proportions.
Two Proportion Test Power is limited to the statistical quantity named by the result panel. The two proportion test power calculation does not silently add a population, time horizon, causal direction, or decision threshold that is absent from the fields.
How the inputs shape two proportion test power
- Group 1 proportion: For two proportion test power, the worked value for group 1 proportion is 0.6 proportion. Treat the group 1 proportion entry (0.6 proportion) explicitly as a count, proportion, rate, estimate, or model parameter before comparing two proportion test power conditions. The form enforces minimum 1e-06, maximum 0.999999.
- Group 2 proportion: For two proportion test power, the worked value for group 2 proportion is 0.4 proportion. Treat the group 2 proportion entry (0.4 proportion) explicitly as a count, proportion, rate, estimate, or model parameter before comparing two proportion test power conditions. The form enforces minimum 1e-06, maximum 0.999999.
- Each group size: For two proportion test power, the worked value for each group size is 100 observations. Treat the each group size entry (100 observations) explicitly as a count, proportion, rate, estimate, or model parameter before comparing two proportion test power conditions. The form enforces minimum 2.
The entries used for two proportion test power must refer to one coherent analysis condition. Combining incompatible populations, periods, or measurement definitions can produce valid two proportion test power arithmetic for a nonexistent study.
The arithmetic used for two proportion test power
For two proportion test power, match every symbol in the relationship to a labeled field before substituting numbers. Two Proportion Test Power is reported in the scale implied by the inputs and formula.
While checking two proportion test power, enter proportions on the scale expected by the labels; 0.40 and 40 are not interchangeable inputs for two proportion test power.
A fixed case for comparison
The default two proportion test power condition is Group 1 proportion = 0.6 proportion, Group 2 proportion = 0.4 proportion, Each group size = 100 observations.
Proportions of 0.60 and 0.40 with 100 observations per group give approximate two-sided normal power of 0.9793 under this page's stated method.
The live calculator reports Approximate power 0.97932491. Repeating one intermediate step from approximate normal power provides a fixed two proportion test power reference check for later code changes.
Statistical context for two proportion test power
Equal group size and a large-sample normal approximation are assumed; sparse cells need another method.
For two proportion test power, power and design calculations are prospective scenarios, not guarantees. For two proportion test power, their answer changes when the planned effect, variance, allocation, alpha, or attrition assumption changes.
When two proportion test power can mislead
When interpreting two proportion test power, report the design inputs as assumptions and compare at least one plausible alternative before committing resources to the plan.
As a second check for two proportion test power, confirm that Group 1 proportion and Each group size cover the same population and time boundary before interpreting the displayed probability or risk.
Varying a single two proportion test power input at a time
Change group 1 proportion while holding the remaining entries fixed, then state why the direction and size of the two proportion test power change are plausible from approximate normal power.
Repeat the two proportion test power exercise with each group size. If a modest defensible change materially alters the interpretation, report both conditions rather than presenting that two proportion test power scenario as exact.
Where a plausible two proportion test power can go wrong
Before accepting two proportion test power, compare every entered value with its label, unit, and allowed domain after reading the printed relationship from left to right.
For two proportion test power, do not move a number between fields merely because the units look compatible; each label gives the number a different statistical role.
Another two proportion test power failure occurs when a rounded output is reused as though it were the original measurement. Carry guard digits through calculations that depend on two proportion test power, then round only the reported value.
What to record with two proportion test power
Report two proportion test power using approximate normal power, followed by the entered values, units, exclusions, and analysis date. Name the two proportion test power population or dataset boundary instead of leaving it implicit.
Keep the full calculator output with the record, including Approximate power 0.97932491. A later two proportion test power review can then distinguish a changed input from a different convention or software implementation.
The surrounding workflow may also require correlation test power.
Questions about two proportion test power
What does two proportion test power represent on this page?
It is the quantity produced by approximate normal power from the displayed group 1 proportion, group 2 proportion, each group size. This page estimates approximate power for comparing two independent proportions.
What should be saved with two proportion test power?
Save the entered values and units for group 1 proportion, group 2 proportion, each group size, along with the analysis date, exclusions, software or formula version, and the relationship approximate normal power. That record is sufficient to rebuild this specific two proportion test power calculation.