Graphical user interfaces for statistical power calculations. (A) PGA1 – statistical power is calculated and plotted for different sample sizes and various genetic and statistical parameters. Input variables (e.g. 'Genetic mode of inheritance', 'disease allele frequency', 'relative risk (RR)', etc.) can be specified using slider controls, or by typing specific values in the corresponding text boxes. Pressing the 'Run' button executes the calculations and plots the relationships between power and sample size according to the specified study parameters. A keyed legend listing the corresponding parameters is shown on the graph. Up to eight different analyses (color-coded) can be displayed simultaneously, allowing the comparison of different scenarios. (B) PGA2 – Minimal detectable relative risk (MDRR) is calculated and plotted for various minor allele frequencies (MAFs) of potential genotyped loci. Input and output is similar to PGA1.