a. Fit a model in R using response variable Y and only the covariate X2 of smoking status. Test if the coefcient on X2 is equal to 0. State the null and alternative hypothesis, the test statistic, p-Value and make a conclusion. b. Now conduct a two sample t-test in R, where the response is resting pulse rate and the two groups / samples are smokers and non-smokers. How does this test correspond to the test from part a