2 In this analysis, you will use customer level data on travel expenditures. You will observe the following variables. Use the dataset "tour_data.RData" for this question. Variables | Description ----------|------------- income | Household income education | Education level of the household head health | Health status index of the household members tripweather | Weather quality in the destination of the trip participation | Dummy variable for tourism participation expenditure | Total household tourism expenditure a) Estimate a regression model of expenditures on income, education, and tripweather. b) Estimate a probit model on participation using income, education, and health c) Estimate a sample selection model of tourism expenditures. d) Compare your estimates in a) and c). Do you detect sample selection bias? How do you know