I understand that adding variables leads to a better representation of random noise, thus a higher R^2, and thus, in multiple regression, it is adjusted for.
In simple linear regression with one variable, there should not be a difference, should there? However, I get different values that are always quite close but not identical.
Is that difference meaningful? Which value is right? For example:
Multiple R-squared: 0.9118, Adjusted R-squared: 0.9109