Diabetes tends to be more prevalent in urban populations, but why this is so is not fully understood. A recent study on mice was designed to investigate the link between diabetes and air pollution. The study involved 28 mice, with 14 randomly selected to have filtered air pumped into their cage while the other 14 breathed particulate matter that simulated common air pollution. The response variable is the amount of insulin resistance each mouse had after 24 weeks. Higher insulin resistance indicates a greater risk for developing diabetes. Data recreated from information in Sun et al. "Ambient Air Pollution Exaggerates Adipose Inflammation and Insulin Resistance in a Mouse Model of Diet-Induced Obesity", Journal of the American Heart Association, 2009; 119 (4): 538-546. (a) Is this an observational study or randomized experiment? O Observational study O Randomized experiment eTextbook and Media Hint (b) If we are interested in whether there is a difference in mean insulin resistance between the two groups, what are the null and alternative hypotheses? Let the filtered air group be group 1, and the polluted air group be group 2. # PI Ho : vs Ha:(c) The difference in sample means from the original sample is D = $1 - X2 = 1.8 - 6.2 = - 4.4. The figure below shows 1000 random assignments of insulin resistant scores from the original sample to each of the two groups. Is it likely we will reject the null hypothesis? Frequency O -3 -2 - 1 0 1 2 Differences O Yes O No eTextbook and Media Hint (d) What is the p-value? Round your answer to one decimal place. p-value = i eTextbook and Media Hint(e) State the conclusion of the test in context. O There is strong evidence that air pollution has no effect on insulin resistance. O Reject Ho- O There is mild evidence that air pollution does affect insulin resistance. O There is strong evidence that air pollution does affect insulin resistance. O Do not reject Ho- O There is mild evidence that air pollution has no effect on insulin resistance