Factorial ANOVA not returning F and p values in TIBCO Statistica
book
Article ID: KB0074414
calendar_today
Updated On:
Products
Versions
Spotfire Statistica
13.1 and higher
Description
When running factorial ANOVA analysis, the output ANOVA table has no values in the F and p value columns. For example, in an experiment study with three factors including site, treatment and brand, and the sample size is 48. Conducting full factorial ANOVA analysis on the data, the F and PÂ value are left as blank in the result.
Environment
Windows
Resolution
This happens because the model specified in the Factorial ANOVA analysis is saturated. The sum of degrees of freedom for fixed effects and interaction terms is 47, which equals the total degree of freedom for this data: N-1=48-1. There is zero degree of freedom left for error.When calculating F and P value, the degree of freedom for error is used as the denominator for computing Mean Square of Error(MSE = SSE/degree of free for error). The computation is impossible with zero in the denominator.
You may consider to eliminate some interaction terms in the factorial design.