Research Question: What is the combined effect of medication and diet on blood pressure in adult males?A randomized, controlled experiment investigated this question using a random sample of 540 adult males as subjects. At the beginning of the study, researchers measured the blood pressure of all the subjects. Each subject was given a month's supply of either Drug A, Drug B, or a placebo, then was assigned to be on either a low-fat diet or a low-salt diet for that month-long period. At the end of the month, the researchers measured the blood pressure of each subject again, and compared the two blood pressure readings.How many different groups are there altogether in this study? 2 3 4 5 6Question 2Select all that apply.10 pointsResearch Question: What is the combined effect of fertilizer and watering on cherry tomato plants?Planters were built that each contained 10 cherry tomato plants. Each planter was identical except that it received a different treatment of water and fertilizer than the other planters. Treatments consisted of a combination of one of four watering schedules and one of three fertilizer concentrations. The plants were tended according to these treatments and after 65 days the average number and weight of the tomatoes per plant were measured for each treatment group.Which of the following is an explanatory variable in this study? Check all that apply. Fertilizer schedule Number of days of treatment Number of plants per planter Number of tomatoes per plant Watering scheduleQuestion 3Select one answer.10 pointsA simple random sample of 1,240 adult Americans is selected, and each person is asked the following question:In light of candidate Jones’s alleged criminal activity do you believe he should withdraw from the race?67% of those surveyed agreed that he should withdraw. Which of the following is an appropriate conclusion about the results? They are reasonably accurate because the study used a large simple random sample. They probably overstate the percentage of people who favor his withdrawal because of the question’s wording. They are inaccurate because of convenience sampling. They are inaccurate because of voluntary response. They probably understate the percentage of people who favor his withdrawal because of the question’s wording.Question 4Select one answer.10 pointsWhich of the following best describes the method of randomized response? A method in which subjects answer the questions in a survey in a random order A sampling method A technique used to minimize the bias in the responses of subjects to sensitive questions A method in which subjects answer each of the