1. Imagine that the dataset data5-1.csv contains data collected from a randomized, parallel group trial with continuous response Y, which is also measured at baseline (pm-randomization). Treatment z=0 is placebo and equivalent to no treatment (e.g., no \"placebo effect\"), and the treatment period is short so we don't expect there to be any systematic change during follow- up in untreated subjects. The variables in the dataset are: 2 Treatment (0,1) bl Baseline value of Y y Follow-up value of Y (a) Plot y versus b1 identifying points with z=0 and z=1 and note features of interest. (b) Now consider just treatment group z=1. i. Perform a paired ttest of the null hypothesis that the baseline population mean is equal to the population mean at follow-up. What does this test tell you