Alpha-error inflation due to optional stopping in data collection for an undirected t-test for differences between means of two-groups given no effect (i.e., H0 is true).
Initial number of participants for each group
Additional number of participants for each group before testing
Maximum number of participants for each group
Repetitions Monte-Carlo simulation
After changing parameters push *Run* to start simulation.
Run
Boxplot of p-values < .05
Data simulations