Hi all,

I'm doing a research about the relationship between risk tolerance and demographic factors such as age, generation, survey year, and control variables (including education levels,...).
1. I have already categorized respondents into 5 different groups ( loweduc, training, university, college, othereduc) but I'm not sure which one to take as the reference category.
2. The data collected is from 1993 to 2019 and I'm doing the test to see if survey years affect their risk tolerance by adding event years and periods of time in the regression. For example, I want to see if 2001 and 2008 crisis affect their responses, and how they reacted in the next 4-year period. So I included 01, 08, 02-05, 09-12 to my model but I have no idea what is the reference category to interpret those dummies.