Question 8 6 pts The histogram below gives the relative frequency histogram of the cholesterol levels for a sample of patients at a hospital. 0.4 0.35 0.3 0.25 0.2 0.15 Relative frequency 0.1 0.05 195 200 205 210 215 220 225 Cholesterol level mmdyzemmom Use the graph to answer the questions below. 1) What percentage of the patients had a cholesterol level of at least 210? [ Select] V 2) What percentage of the patients had a cholesterol level between 200 and 220? 3) If this sample represented 400 patients, how many of them had a cholesterol level between 200 and Consider the following: A researcher obtained a random sample of 100 smokers and a random sample of 100 nonsmokers. After interviewing all 200 participants in the study, the researcher compared the rate of depression among the smokers with the rate of depression among nonsmokers. All responses must be in full sentences. 1. Is this an observational or experimental study? Briey explain your choice. (4 pts) 2. What is the response variable? (2 pts) 3. What is the explanatory variable? (2 pts)