Today when I run a regression (in specific Difference-in-Differences but I think it does not matter here). My outcome variable is a ratio (lower than 1 million, it is about the number of people per million).

I have two questions here:
  1. Whether I should use log for this outcome variable because I am not sure it is a ratio or actual value (ratio to me normally percent, not per million like that)?
  2. I run the regression with the outcome above and the coefficient of a dummy variable is 2 (higher than 1), is it abnormal? (The dummy here only receive the values of 0 and 1)