Exer 7.1 [E/E114]  

AGid

The R2 statistic is the ratio of the variance of the fitted values to the variance of the response variable.

Using the kidsfeet data:

  1. Find the variance of the response variable in the model width ~ sex + length + sex:length .
     0.053  0.119  0.183  0.260  0.346  
  2. Find the variance of the fitted values from the model
     0.053  0.119  0.183  0.260  0.346  
  3. Compute the R2 as the ratio of these two variances.
     0.20  0.29  0.46  0.53  0.75  
  4. Is this the same as the “Multiple R2” given in the summary(mod) report?
     Yes  No