- Thread starter nicolecharles
- Start date

If you're concerned about normality or other assumptions for ANOVA, you may consider a nonparametric rank regression (just understand you're looking at mean rank for length of stay vs mean length of stay)...there are equivalencies to recognize when using a regression model with a quantitative response and only categorical variables vs using the "ANOVA." You can derive the same answers, but seeing the connection can provide a bit of flexibility and extra interpretable output.

Otherwise, I would agree with the two-way ANOVA.

There seems to be four factors (knee replacement and Hip, race groups, insurance types, different age groups) where age could be a covariate = a regression variable.

I would guess that this is not a balanced design (They have hardly randomized people to different treatments) so I guess that the full factorial can not be estimated. But I guess that the main effects can be estimated.

Maybe OP can give us some descriptive statistics so we can see the number of observations in each group so we can get a better idea on the project.