You are designing the user interface to a production application in which the time it takes users to perform a task is a good measure of productivity (the faster, the better). You've done a survey of the end users with 3 different user interface designs, and they don't prefer one over the other. The raw data is listed below for the different users who have performed the tasks, with each user performing the task with all three prototypes. Perform an analysis of variance on these data to determine if one interface provides a performance advantage over the others. If the ANOVA is significant, perform the Tukey-Kramer procedure using PHStat to determine which Prototype offers superior user performance.
See attached file for data.
This solution provides answers to questions regarding a user interface for a production application.