# Multiple Linear Regression - categorical variables

I have a categorical independent variable along with other continuous independent variables. Should I dummy code it or should I just treat it as a nominal variable?

That depends on how your statistics software handles categorical variables. In R, they are called factors, and if you include a factor in a regression model, it will automatically be dummy coded. However, if the categorical variable is not a factor, but a numerical variable, R will handle it as such, and you will need to specify it as a factor: factor(variable) to use it as a categorical variable (and R will create the dummy variables for you).