After having fit a multiple regression model to my data, I am using it for predicting my dependent variable. I understand how one can predict and compute (using R) two tailed prediction intervals at a certain $\alpha$. The requirements of the use case are such that I don’t care about the upper prediction (two-tailed) interval because I need to be able to say that with 100(1-$\alpha$)% confidence that the value I have predicted will be above the prediction limit. My questions:
- Is it statistically valid to compute one tailed prediction interval for linear regression? I searched on CV for questions related to this and could not find anything.
- If yes, then could one use the
predict()function in R to compute the interval? I have read the documentation of the function, it does not seem to have an option to switch between one-tailed and two-tailed. Otherwise, how could one calculate such an interval in R?