Explanations 
Textbooks 
Flashcards 
91影视 AI 
Notes 
Study Plans 
Study Sets 
Find a degree 
Magazine Problem 4
Many colleges are moving toward coed dormitories. A Residential Life director plans to sample student attitudes toward this arrangement. He randomly selects three of the 12 dorms and sends a questionnaire to all residents living in them. Which of the following best describes the director's sampling plan? (A) A convenience sample (B) A simple random sample (C) A stratified random sample (D) A cluster sample (E) A systematic sample
Problem 5
To survey the opinions of bleacher fans at Wrigley Field, the home stadium of the Cubs baseball team, a surveyor plans to select every one-hundredth fan entering the bleachers one afternoon. Will this result in a simple random sample of Cub fans who sit in the bleachers? (A) Yes, because each bleacher fan has the same chance of being selected. (B) Yes, but only if there is a single entrance to the bleachers. (C) Yes, because the 99 out of 100 bleacher fans who are not selected will form a control group. (D) Yes, because this is an example of systematic sampling, which is a special case of simple random sampling. (E) No, because not every sample of the intended size has an equal chance of being selected.
Problem 5
In designing an experiment, blocking is used (A) to reduce bias. (B) to reduce variation. (C) as a substitute for a control group. (D) as a first step in randomization. (E) to control the level of the experiment.
Problem 6
Each of the 30 MLB teams has 25 active roster players. A sample of 60 players is to be chosen as follows. Each team will be asked to place 25 cards with its players' names into a hat and randomly draw out two names. The two names from each team will be combined to make up the sample. Will this method result in a simple random sample of the 750 baseball players? (A) Yes, because each player has the same chance of being selected. (B) Yes, because each team is equally represented. (C) Yes, because this is an example of stratified sampling, which is a special case of simple random sampling. (D) No, because the teams are not chosen randomly. (E) No, because not each group of 60 players has the same chance of being selected.
