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Barlas · IndividualStatistics

Sample Size & Power

Estimate planning sample sizes from your precision or effect target and stated assumptions.

Example result · fictional data0 observations

Plan sample size

Required observations
62
Target margin
3 outcome units
Approximate achieved margin
2.987 outcome units

Precision by sample size

Precision by sample size. Independent observations versus Margin of error (outcome units). 7 plotted observations.2345616 observatio…16 observations47 observatio…47 observations93 observatio…93 observations186 observati…186 observationsIndependent observationsMargin of error (outcome units)16 observations · Independent observations: 16 · Margin of error (outcome units): 5.87989195362012231 observations · Independent observations: 31 · Margin of error (outcome units): 4.224239080858982547 observations · Independent observations: 47 · Margin of error (outcome units): 3.43068155929335162 observations · Independent observations: 62 · Margin of error (outcome units): 2.98698809942861593 observations · Independent observations: 93 · Margin of error (outcome units): 2.4388655704552704124 observations · Independent observations: 124 · Margin of error (outcome units): 2.1121195404294912186 observations · Independent observations: 186 · Margin of error (outcome units): 1.7245383832713195

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How it works

  1. Choose mean precision, proportion precision or a two-group difference.

  2. Enter the requested precision or effect and the planning assumptions.

  3. Review the estimated sample size and the approximation notes.

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