User Guide

The page for each calculator is organized into two primary sections. The top section contains the calculator interface and the corresponding output. The bottom section provides supplementary information and a navigation menu.

• Upon opening a calculator, you will find the input fields pre-populated with example values. These can be replaced with your study's parameters. Please adhere to standard constraints, such as using only numeric values for numerical inputs, ensuring variances are positive, and keeping probabilities within the 0 to 1 range.
• All input fields must be completed to perform a calculation. The resulting sample size is shown at the top of the input form.
• Once you have entered your desired parameters, click the button at the bottom of the form. This will update the required sample size and regenerate the accompanying plot.
• The calculated sample size is always rounded up to the next integer. This rounding may result in a step-like appearance in the power curve plots.

• The plot serves as a visual tool to illustrate the sensitivity of the sample size calculation to changes in the input parameters.
• The vertical axis (y-axis) consistently represents the required sample size. The parameter plotted on the horizontal axis (x-axis) can be selected using the dropdown menu located beneath the plot.
• The range of the x-axis can be modified in two ways: by using the slider control or by manually entering minimum and maximum values into the corresponding input fields.
• The plot displays multiple curves, typically two or three, each corresponding to a different level of statistical power. The legend positioned above the plot clarifies the power level associated with each curve.
• Hovering the cursor over the plot will display the specific sample size and parameter value for the corresponding point on the curve in the legend area.