Hello Kimberly,
As Ralph mentions, you will need to use different statistical tests depending on the type of variable you're analyzing. In Lecture 1, Mark reviews the various statistical tests that can be used for different types of variables. On slide 37, he reviews statistical tests for 2 categorical variables. On slide 41, he reviews various statistical tests for 1 categorical variable and 1 continuous variable. Hope that helps, and please let us know if you have more questions.
Thanks!
ellie