Question

3. Suppose a random sample of 300 U.S. college students was obtained and the average number of hours of sleep per night for each individual was determined. It was then determined that those students who averaged at least 7 hours of sleep per night had a higher cumulative gpa, on average, than those who did not Define the following: (a) The population(s) of interest.(The independent variables) (b) The variable measured.(The dependent variable). Is this an observational study or experiment? (c) Parameter(s) of interest. (d) Inference of interest.(The research inference) (e) Is the causal inference "more sleep increases gpa" supported by this study? Jus- tify your answer

Answer 1

A) Population of Interest is the U.S. college students from which a sample of 300 students is collected

B) The variable measured is the number of hours of sleep per night by each individual

This is an Observational study as we are observing the sleep pattern of the students. This is not an experiment

C) Parameter of interest is the Mean number odf sleep hours of U.S. students in one day

D) Inference of Interest is the dependence of GPA on the number of sleep hours. Here, the Inference is that students who enjoy 7 hours of sleep a day excel in GPA as compared to those who do not have adequate sleep of 7 hours

E) No, the causal inference that 'more sleep increases gpa' is not supported by the study. Instead, the study is just a Statistical Inference which suggests that an adequate sleep of 7 hours produces better results as the mind is relaxed. However this does not suggest that if a person sleeps for 14 hours, then he would get better results. This is not the truth.