2. Exercise Stress Test. Campbell and Swinscow (2009) describe an experiment in which twenty patients, ten of normal weight and ten severely overweight underwent an exercise stress test. The patients had to lift a progressively increasing load for up to 12 minutes, but they were allowed to stop earlier if they could do no more. On two occasions the equipment malfunctioned before 12 minutes. The times (in minutes) achieved were: Normal weigh 2, 4, 6, 8, 8, 9, 10, 12 , 12 , 12 Overweight 1, 3, 4, 5, 6, 7, 7, 9, 11, 12 Here, means that the end of test was reached, and stands for equipment malfunction. Assume that the equipment does not fail and test does not have 12 minutes time limit, that is, all subjects are to stop only if they could do no more. Compare mean times to stopping for the two groups. Is the difference in mean times significant? Hint. Propose a parametric model, use censoring, and set noninformative priors on all parameters. There is no a unique way to model this data.