Using a data set from R, I need to find a 95% CI to predict a female with average study, homework, and scores would pass SAT. Then I need to repeat the prediction for a female with maximal values for study, hw and scores and determine which is wider.
I know I have to do a
predict() using my original to get the average lm given
fit<-lm(sat ~ study + homework + score + gender)
Problem: I don't know how to predict with maximal values for the variables or determine which is wider.