KEY FEATURES: Introduces students to developing research questions and shows their importance in driving research design. Rarely taught topics, such as how to enter and clean data, offer students information missed in both research methods and statistics courses. Shows how to write up survey results for academic, business and nonprofit reports to alleviate the confusion students feel about how to write up findings. Rigorous treatment of sampling focuses on many sampling issues from probability theory to weighting. Offers the process of actually conducting a survey with advice on administering surveys, incentives, and improving response rates.

# How Do We Interpret OLS Regression With a Categorical Independent Variable?

### How Do We Interpret OLS Regression With a Categorical Independent Variable?

In Q84, we examined group differences in a continuous dependent variable using a t-test or an ANOVA. Regression provides similar results with a single categorical independent variable. If we regress income on gender, the equation is Income = a + b1*male. The variable “male” is a dummy variable created from the dichotomous gender variable. Male = 0 for all the females, and male = 1 for all the males. Recall that the intercept is the value of Y, or income in this case, when the X variable (gender) equals 0. Well, when male = 0, we have all the females. Therefore, in a regression with a dummy variable, we can interpret the ...