In a survey of introductory statistics students, an instructor asked her students to report how many hours they spent studying in a typical week during the last term and their sex. Suppose that the intent is to compare reported study habits of male students to those of female students.
a. Is this an experiment or an observational study? Explain how you know.
b. Identify the observational units.

c. Identify the explanatory and response variable. Also, identify whether each is quantitative or categorical.
d. Identify the appropriate null hypothesis from the following set of five choices.
A. Male students and female students are equally likely to study.
B. On average, male students and female students spend an equal amount of time studying.
C. On average, female students spend a greater amount of time studying compared to male students.
D. On average, female students spend a lesser amount of time studying compared to male students.
E. On average, female students diff er from male students when it comes to how much time they spend studying.

e. Identify the appropriate alternative hypothesis from the following set of five choices.
A. Male students and female students are equally likely to study.
B. On average, male students and female students spend an equal amount of time studying.
C. On average, female students spend a greater amount of time studying compared to male students.
D. On average, female students spend a lesser amount of time studying compared to male students.
E. On average, female students diff er from male students when it comes to how much time they spend studying.