# Runs don't change in a strip plot DOE when hard to change factors changes are not independend from very hard factors?

[#1]

I have a strip plot DOE with 2 very hard and 2 hard to change facors, also 2 are easy to change. With my model I get 8 whole plots and 16 subplots with 48 runs However when I don't allow the hard to change factors to change independend from very hard the number of runs remain the same? Allowing all whole plot x subplot conbinations should give significantly more runs?

[#2]

Hi Victor, thanks for analysis & explanation, this is clear. My question is why the #plots don't change automatically when changing from indepent to dependent?

Regards from Sorrento, I am leaving, was a great discovery event!

[#3 · Accepted solution]

JMP will change the number of plots or subplots only if there isn't enough degree of freedom to fit the assumed model. In this case, you just have the minimum number of subplots to provide enough DFs for the fitting of the assumed model, so JMP let you continue, but add a warning message that the subplots variance won't be estimable.

Looking forward to meeting you at a next event ! Have a safe trip back.

[#4]

OK, thanks, it would be nice if JMP would also specify the required minimum # subplots. Hope to see you next time as well.