Читать книгу Business Experiments with R - B. D. McCullough - Страница 19

1 1.1.1 Find an example of an observational study. Answer the following questions: (i) What makes this an observational rather than an experimental study? (be specific) (ii) What is the purpose of the study? (iii) What is the primary variable of interest?

2 1.1.2 For each of the following, indicate whether the data are observational or experimental, and defend your answer.A broadcaster moves a popular television show from Tuesday to Thursday, and its viewership increases.A psychologist wants to know how often students take a break from studying. To do this, he installs cameras in the library's reading room for one day. He notes that students take more breaks in the evening.A sports manufacturer wonders if his quick‐dry exercise shirts dry more quickly than regular shirts. He finds some basketball players playing a game in the gym. He gives one team quick‐dry shirts, and the other team gets regular 100% cotton shirts.A child psychologist asks several parents whether their children play violent video games. He also asks how many times a week their children display violent behavior. He finds that children who play violent video games display more violent behavior.

3 1.1.3 Give two situations where experiments can't be conducted.