Z Z value eg. John Wiley and Sons Inc. Cochrans sample size formula for categorical data for an alpha level a priori at 05 error of 5 n0t2pqd2384 Where.
In our earlier example if there were just 1000 households in the target population we would calculate 385 1 384 1000 278.
The Cochran formula isThen the sample size can be estimated by Necessary Sample Size z-score2 StdDev 1-StdDev margin of error2. An additional calculator tool in Excel format is available that performs many of the same functions for dichotomous and continuous data with the added benefit that you can save your calculations for future reference. Here are the formulas used in our Sample Size Calculator. Study Group Design vs.
