regression. T 20. Drug use 2013 The 2013 World Drug Report investi- gated the prevalence of drug use as a percentage of the population aged 15 to 64. Data from 32 European coun- tries are shown in the following scatterplot and regression analysis. (Source: World Drug Report, 2013. www.unodc .org/unodc/en/data-and-analysis/WDR-2013.html) 3.00 2.25 1.50 0.75 4 8 12 Canabis (%) Response variable is Cocaine R-squared 25.8% = s = 0.7076 with 32 2 = 30 degrees of freedom - Variable Coefficient SE(Coeff) t-Ratio Intercept 0.296899 0.2627 1.13 Canabis 0.123638 0.0382 3.23 Cocaine (%) P-Value 0.2673 0.0030 a) Explain in context what the regression says. b) State the hypothesis about the slope (both numerically and in words) that describes how use of marijuana is associated with other drugs. c) Assuming that the assumptions for inference are satisfied, perform the hypothesis test and state your conclusion in context. d) Explain what R-squared means in context. e) Do these results indicate that marijuana use leads to the use of harder drugs? Explain