is time regressors ols how many city observations are on a census panel when is time variable used for ols why do ols use time variable why do we not include time variables in data analysis? why is the variable of city population not considered a dependent variable? when are time and period variables used in census data what is the effect of not using the time variable in ols what is the impact of not using the time component on ols what is the time variable in city data what is the implications for ols in data can I use time and regressors in my data? why is the time variable not included in ols what is the implications for ols what is the effect of not using the time variable? why don't ols use time can you use time in a data set why don't we use time in panel data what is the implications of not using time in data why can't ols include time variable in data