Refer to the creatine phosphokinase data on 1005 subjects (PCKDATA). Researchers would like to know if psychologically stressful situations cause an increase in serum creatine phosphokinase

(CPK) levels among apparently healthy individuals. To help the researchers reach a decision, select a simple random sample from this population, perform an appropriate analysis of the sample data, and give a narrative report of your findings and conclusions. Compare your results with those of your classmates.