Hey!
In my statistical book, I came across recoding the variables in simple regression. I know how to record variables in order to have the values of 0 and 1. However, in the book there is written that before recording, there is a need to execute this command:
dataset$biology <- NA.
I cannot get what this NA means in this particular command, I know that it should refer to missing values but what is the exact meaning here?
Thanks