Help with a,b,c,d,e thanks

Problem #1: A study is being conducted to determine which intensity level of cardio exercise is effective in reducing weight among overweight adults ages 30-50. A random sample of 100 overweight adults in this age range was selected and randomly assigned to one of the three intensity levels of cardio exercise (low, moderate, high) or the control group (no cardio exercise). Although the participants know which group they are participating in, the dietitian that will measure their weights at the end of 4 weeks does no know which group each participant was assigned to. a. Justify why this problem is an example of an experimental study. b. Is the study double-blind? Why or why not? c. The variable 1'11 tensity level of cardio exercise is in what level of measurement? d. Identify the response variable and explanatory variable in the study. e. Cite some examples of extraneous variable that may inuence the response variable