1. In a cross sectional dataset we observe the same individual multiple times. O True O False 2. The trim-and-fill method is used address the problem of heteroskedasticity. O True O False 3. The letter n is typically used to refer to total number of variables included in a regression. O a. True O b. False 4. The letter N is typically used to refer to the total number of observations in the Population O a. True O b. False