I just ran a regression using
- time (year)
- sex (Male = 0; Female = 1)
- the interaction between the two.
I chose not to recode the year variable (i.e., 2000 = 1, 2001 = 2, etc.) for this analysis, as I've read that doing so only impacts the intercept (per another post on this site). These were the results I obtained from this analysis:
However, when I recode the year variable using the scheme noted above (while making no other changes), these are the results:
Why would changing the coding scheme for the year variable reverse the sign of the coefficient for "Female?"