Sample size for testing non-inferiority between two independent means using a t-test

Note: The direction of the test is assumed depending on the ordering of the input values for 'Mean difference' and 'Non-inferiority' margin. For inputs with 'Mean difference' < 'Non-inferiority margin', it is assumed that the aim is to show that the mean difference is indeed smaller than the non-inferiority margin. For inputs with 'Mean difference' > 'Non-inferiority margin', it is assumed that the aim is to show that the mean difference is indeed greater than the non-inferiority margin.

Mean difference

Non-inferiority margin