# How to interpret the intercept in a regression model which has a categorical covariate?

#### arkm25

##### New Member
I have a regression model with some response Y and covariates height, weight, age, sex.
Sex is the only categorical covariate and it takes on the value
Sex = 0, for female
Sex = 1, for male

I want to interpret the intercept of this model, that is the estimated mean value of Y when all the covariate coefficients are zero.
But I don’t understand how to view a zero coefficient in front of a categorical variable such as sex. If all coefficients are zero, am I looking at 0 height, 0 weight, 0 age, no sex. Or am I looking at 0 height, 0 weight, 0 age, female, since sex = 0 represents female?

In other words, does sex having a zero coefficient represent no sex or does it represent female?

#### hlsmith

##### Less is more. Stay pure. Stay poor.
Represents female, the reference group. You also have to rationalize in your mind such a person does not exist, since it is impossible to have a wt, age, ht of '0'. Many people will standardized the continuous variables before entering them into the model, which would represent the mean of the continuous variables for a females.

Good luck.