Paired Mean Test Power Calculator
Estimates power for a paired-mean design from the expected within-pair difference. The form displays approximate normal power beside paired mean test power, using a worked condition that can be recalculated with the labeled inputs.
Set the labeled inputs
Paired Mean Test Power
Purpose of this paired mean test power calculation
The paired mean test power page estimates power for a paired-mean design from the expected within-pair difference.
Paired Mean Test Power is limited to the statistical quantity named by the result panel. The paired mean 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 paired mean test power
- Expected paired difference: For paired mean test power, the worked value for expected paired difference is 2 units. Treat the expected paired difference entry (2 units) explicitly as a count, proportion, rate, estimate, or model parameter before comparing paired mean test power conditions.
- SD of paired differences: For paired mean test power, the worked value for sd of paired differences is 4 units. Treat the sd of paired differences entry (4 units) explicitly as a count, proportion, rate, estimate, or model parameter before comparing paired mean test power conditions. The form enforces minimum 1e-06.
- Number of pairs: For paired mean test power, the worked value for number of pairs is 30 pairs. Treat the number of pairs entry (30 pairs) explicitly as a count, proportion, rate, estimate, or model parameter before comparing paired mean test power conditions. The form enforces minimum 2.
The entries used for paired mean test power must refer to one coherent analysis condition. Combining incompatible populations, periods, or measurement definitions can produce valid paired mean test power arithmetic for a nonexistent study.
How paired mean test power is calculated
For paired mean test power, match every symbol in the relationship to a labeled field before substituting numbers. Paired Mean Test Power is reported in the scale implied by the inputs and formula.
While checking paired mean test power, change Expected paired difference by a small controlled amount and predict the direction of paired mean test power before recalculating.
Verifying the default paired mean test power result
The default paired mean test power condition is Expected paired difference = 2 units, SD of paired differences = 4 units, Number of pairs = 30 pairs.
A paired difference of 2 with paired-difference SD 4 and 30 pairs gives approximate two-sided normal power of 0.7819.
The live calculator reports Approximate power 0.78189745. Repeating one intermediate step from approximate normal power provides a fixed paired mean test power reference check for later code changes.
For a related comparison, continue with one proportion test power.
Assumptions behind paired mean test power
Power depends on the spread of differences, not the separate spreads before and after pairing.
For paired mean test power, power and design calculations are prospective scenarios, not guarantees. For paired mean test power, their answer changes when the planned effect, variance, allocation, alpha, or attrition assumption changes.
When paired mean test power can mislead
When interpreting paired mean 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 paired mean test power, if that direction is surprising, recheck the units and the role of Number of pairs in approximate normal power before accepting the display.
A practical stress test for paired mean test power
Change expected paired difference while holding the remaining entries fixed, then state why the direction and size of the paired mean test power change are plausible from approximate normal power.
Repeat the paired mean test power exercise with number of pairs. If a modest defensible change materially alters the interpretation, report both conditions rather than presenting that paired mean test power scenario as exact.
Where a plausible paired mean test power can go wrong
Before accepting paired mean test power, compare every entered value with its label, unit, and allowed domain after reading the printed relationship from left to right.
For paired mean 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 paired mean 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 paired mean test power, then round only the reported value.
Rebuilding this paired mean test power calculation later
Report paired mean test power using approximate normal power, followed by the entered values, units, exclusions, and analysis date. Name the paired mean test power population or dataset boundary instead of leaving it implicit.
Keep the full calculator output with the record, including Approximate power 0.78189745. A later paired mean test power review can then distinguish a changed input from a different convention or software implementation.
Questions about paired mean test power
Why could another program report a different paired mean test power?
A different convention for rounding, tails, ties, interpolation, parameterization, or missing values can change paired mean test power. Compare the printed paired mean test power formula and its input definitions before treating either output as wrong.
What does paired mean test power represent on this page?
It is the quantity produced by approximate normal power from the displayed expected paired difference, sd of paired differences, number of pairs. This page estimates power for a paired-mean design from the expected within-pair difference.