search for: incteractions

...nd the third code doesn't allow me to define my variables as factors becuase it uses character strings (and therefore runs a lot more models than necessary). Is there a way to use the third code, but tell R that some of the character strings are factors? Otherwise, since there are a lot more incteractions that I do not wish to test than interactions that I do wish to test, is there an alternative by which instead of having to exclude the interactions that I do not wish to test, I can simply run models with the interaction terms that I include in my lm fromula? Thank you in advance for your time,...

...and the third code doesn't allow me to define my variables as factors becuase it uses character strings (and therefore runs a lot more models than necessary). Is there a way to use the third code, but tell R that some of the character strings are factors? Otherwise, since there are a lot more incteractions that I do not wish to test than interactions that I do wish to test, is there an alternative by which instead of having to exclude the interactions that I do not wish to test, I can simply run models with only the interaction terms that I include in my lm formula? Thank you in advance for your tim...