Are two regression lines equivalent? ANCOVA versus Fit Line.
I have a data set in which 2 response variables were collected (JO2 and dPsi) under 5 different energy states (dGATP) for subjects on two different diets (PM or SR; grouping variable). I used the Fit Model platform to plot the individual subject data and compare whether a linear or quadratic model would be optimal. The AIC was lower for the linear model for both individual and grouped data and m...