Suppose that we want to evaluate the e ect of several variables on annual saving and that we have a panel data set on individuals collected in January 1990 and January 1992. If we include a year dummy variable for 1992 and use rst di erencing, can we also include age in the original model ? Explain

True of false: the chancellor of a university has commissioned a team to collect data on students' gpas and the amount of time they spend bar hopping every week (measured in minutes). he wants to know if imposing much tougher regulations on all campus bars to make it more difficult for students to spend time in any campus bar will have a significant impact on general students' gpas. his team should use a t test on the slope of the population regression.