I have the following experimental design:

Dependent Variable: time taken for task

Independent Variables: task difficulty(2), device configuration(5)

Participants are randomly assigned to one task difficulty (easy or hard). They then go through all 5 device configurations (which are randomized for order) and the time taken for each task is recorded. In addition, for each device configuration, they do that task twice in a row.

I have pilot data from 8 participants. I'm trying to do a power analysis and figure out roughly how many participants I will need for the full study. I'm trying to use this software:

http://www.stat.uiowa.edu/~rlenth/Power/index.html

Based on my design, I think it should be a nested factorial design (ANOVA). From there, I guess I can put in the standard deviations and wanted power level to identify how many participants will be needed.

Does this sound like I am using the correct ANOVA in the tool?

Does anyone know what the detectable contrast value that can be set is in the tool?

Am I on the right track?

Thanks in advance.