The mat two questions (17 and 18) refer to the following: Is there a relationship between marijuana use and use of other illegal dmgs? A survey was conducted in the United States and nine oountria in Watcrn Europe. The percentage X of teenagers who have used marijuana and the percentage Y who have used other illegal drugs are as follows: Country % Marijuana % Other Drugs Czech Republic 22 4 Denmark 3 England 21 Finland 1 Ireland 16 Italy 8 Northern Ireland 14 Norway 3 Portugal 3 United States 24 The correlation between marijuana use and other drug use is calculated to be 1' = 0.89 and the least squares regression line is calculated to be 37 = -2.55 + 0.58:. 17. Which of the following statements is true? (A) A good prediction for the percentage of teens v19 have used other drugs in Scotland (where 53% have used marijuana) is 28.19%. ' (B) About 79% of the variation in other drug use can be accounted for by its regression on marijuana use. (C) It is clear that marijuana. is a. "gateway drug"; that is, marijuana use leads to use of other illegal drugs. (D) It is clear that most teens who have used other illegal drugs have also used mari- juana. (E) all of the above 18. What is the value of the residual for Denmark? (A) 7.31 (B) 7.31 (C) 3.81 (D) -4.31 (E) 4.31 43