I have a relative straight forward question.
Lets say we have a typical multiple regression model. With lets say 3 different independent variables. If one independent variable with its beta parameter has a very low value compared to the other parameters, lets say 0.00025.
Would it be better to not include this variable in the model?
$$ \log y = 5.32 + 0.3\log(x_1) +0.15(x_2) + 0.00025(x_3) + u $$ where y is measured in pounds and the independent variables are measured in percentages.