Can some boy help with these questions ?

QUESTION 8 The measure R- is used primarily to monitor whether extra explanatory variables really belong in a multiple regression model Truc O False QUESTION 9 When analyzing visitor numbers at an amusement park in Florida, one of the variables in the dataset is the month when they data was recorded. To include this categorical variable in a regression, dummy variables for each month should be created and included in the regression. O True False QUESTION 10 If we believe that the effect of earning a Graduate degree on income depends on gender, then we should include an interaction variable between Graduate degree, income and a gender dummy variable O True False QUESTION 11 A time series can be decomposed inc O a. base series O b. trend O t. seasonal component O d.cyclic component O e. all of these options