- Select the type of calculation. You may choose either to calculate power (default) or total sample size.
- If you change the type of calculation, press the
*Change Type of Calculation*button. - Boxes with a yellow background are for your input. Boxes with a blue background are
calculated by the program.
- If you are calculating power, enter a sample size in the total sample size text box. Values in the power text box are ignored.
- Likewise, if you are calculating sample size, a value in the total sample size text box is ignored. Enter a power in the power text box.

- Select test type: Choose either to make a one-sided (default) or two-side test.
- Enter values for P1, P2, alpha (default .05), and power. These values must be in the open interval (0,1).
- Enter a value for the sample size ratio 2-1 (default 1.0). It must be positive.
- Do not use comma separators for numbers (eg. enter '1000', not '1,000').
- Press the
*Calculate*button to make the calculation for power or total sample size.