Question

Research question: Amongst Penn State World Campus students, do those who sleep more tend to have higher grade point averages (GPAs)? Researchers are going to collect data from a sample of 100 Penn State World Campus students. They will call each student to ask how many hours they slept last night and they will ask each student for their GPA (scale of 0 to 4.0).

1. Is this an observational or experimental research study? Explain how you determined this.

2. Identify the cases and the variables in the study.

3. Identify the intended population and the sample in the study.

4. Is hours slept last night a categorical or quantitative variable?

5. Is GPA a categorical or quantitative variable?

6. What are the explanatory and response variables in this study? Explain how you identified these.

Answer 1

1. Observational study because we are not intervening to manipulate any of the variables , rather we are just observing some past data.

2. Cases : Each of the 100 Penn State students who get sampled. ; Variables : Sleep duration on last night, GPA.

3. Intended population : Set of all Penn State World Campus students ; Sample : A randomly sampled 100 students of Penn State campus.

4. Hrs slept : Quantitative variable because there is notion of ordering i.e. 5 hr is more than 4 hr etc.

5. GPA : Quantitative variable because there is notion of ordering i.e. GPA 3.7 is better than GPA 3.5

6. Explanatory : Hours of sleep last night ; Response : GPA ; This is identified from the initial statement of the paragraph : " Do those sleep more tend to have higher GPA? " in which it is clearly seen that one is interested in causal relation where sleep hrs is cause and GPA is effect.