r confidence intervals

  1. A

    Interaction

    Hi, In your opinion is this a multiplicative qualitative or quantitative interaction?
  2. R

    Fitting confidence interval lines in R using the predict function

    Hi everyone, I am currently attempting to fit confidence interval lines to a regression model in R, but every time I try to for example add a +2 confidence interval line, I end up with two of them! I have been over my code many times and can't find any obvious mistakes. This is the code I...