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JMP ANOVA giving wrong number of degrees of freedom

Hello,

 

Brand-new to JMP, so my apologies if I'm doing something obviously wrong to you, the wise ones. I am trying to run a two-factor ANOVA on a dataset that involves battery test life at 3 different temperatures using 3 different materials. When I run "Fit Model" using JMP, however, I get only 1 degree of freedom for each of my effects, not 2 like I would expect (3 data points - 1 = 2 degrees of freedom). This is causing a pretty nasty overestimation of my F-ratios and p-values that are way too small. I have attached the raw .jmp file I am using, my model specification dialog, and the output I am getting from the model. What am I doing wrong?

 

Best,

Jordan

Data TableDOEOtherRe: JMP ANOVA giving wrong number of degrees of freedom

It looks like JMP is completely missing my T=70 degrees condition. This is truly bizarre. 

Re: JMP ANOVA giving wrong number of degrees of freedom

Sure enough, I was just interpreting this incorrectly. I assumed JMP would use an effects model with n-1 degrees of freedom, but since I set temperature to be a continuous variable, JMP was actually using a regression model with a lower number of degrees of freedom (1). By adding a temperature * temperature term I can bring the degrees of freedom up to 2, or by changing temperature to a categorical variable (not a continuous one).