Experimental DesignName______
1. To determine the effectiveness of a new diet drug, researchers used 16 mice and 16 rats that were considered to be overweight. Eight of the mice and 8 of the rats were chosen at random to receive the drug. The remaining mice and rats were given a placebo. The researchers who actually worked with the animals did not know which group received the placebo. The change in weight was measured for each subject. The design of this experiment is
a. completely randomized with one factor, drug
b. completely randomized with one factor, species
c. randomized block, blocked by drug and species
d. randomized block, blocked by drug
e. randomized block, blocked by species
2. A television network asked its viewers to vote for the best team in college football. It gave a telephone number that viewers could call to vote for their favorite team. Each caller was charged $1 for their call which was donated to charity. Of the 23,000 people who responded, 53% voted for Team A. What does this survey show?
a. this was a legitimate sample since it is so large.
b. this survey was drawn from interested viewers who would be knowledgeable about football.
c. the results are unclear since the location of the viewers is not known.
d. the study is valid since the population is at least 10 times as big as the sample
e. the survey is not valid because the responses were voluntary
3. A surveyor selects every tenth person entering a local shopping mall on Thursday morning. Will this give a simple random sample of local shoppers?
a. no, because the surveyor did not use stratification.
b. yes, because each shopper has an equal chance of being selected.
c. no, because some shoppers would be under-represented on Thursday mornings
d. yes, this is a systematic sample
e. no, the surveyor should have used cluster sampling
4. A local t.v. station conducts a telephone call-in poll to see if a basketball coach at a local university should be fired. 23 people call the station, 16 of whom believe the coach should be fired. What is the population in this poll?
a. all viewers of the station
b. all basketball fans in the town.
c. the 16 people who believe the coach should be fired
d. the 23 people who phoned in
e. the fans who attend the basketball games
5. In a survey about smoking habits, a junior high school student deliberately gives an incorrect answer. This is an example of
a. sampling errord. human mistake
b. response biase. voluntary error
c. hidden bias
6. Which of the following statements must be true about blocking?
I. Blocking is used whenever matched pairs cannot be used.
II. Blocking is a convenient way to control several independent variables.
III. It produces segmentation of the population.
a. I onlyd. I, II, and III
b. II onlye. II and III only
c. III only
7. Why is blocking used in experiments?
a. to reduce variabilityd. to randomize properly
b. to check for the placebo effecte. to increase the cause and effect relationship
c. to reduce bias
8. At Roosevelt HS, a new math program is being tested. The students are asked to either join the traditional program or the experimental program. The teachers are then randomly selected to teach one of the classes. At the end of the course, all students take the same exam and the grades for the two classes are compared. Comment on the design of this experiment.
9. Design a study comparing student scores on a standardized test after using two different types of textbooks.
10. Tell what type of sampling each of the following are.
a. Obtain a list of patients discharged from all MMH facilities. Divide the patients according to length of hospital stay. Dras sinple random samples from each group.
b. Obtain lists of patients discharged from all MMH facilities. Number these patients and then use a random-number table to obtain the sample.
c. Randomly select some NMH facilities from each of five geographic regions, and then include all the patients on the discharge lists of the selected hospitals
d. At the beginning of the year, instruct each NMH facility to survey every 500th patient discharged.
e. Instruct each NMH facility to survey 10 discharged patients this week and send in the results.
11. Which of the following are true statements?
I. In an experiment some treatment is intentionally forced on one group to note the response.
II. In an observational study information is gathered on an already existing situation.
III. Sample surveys are observational studies, not experiments.
12. To survey the opinions of bleacher fans at Wrigley Field, a surveyor plans to select every one-hundredth fan entering the bleachers one afternoon. Will this result in a SRS 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 SRS.
e. No, because not every sample of the intended size has an equal chance of being selected.
13. Consider the following three events, and tell the type of Bias in each.
I. Although 18% of the student body are minorities, in a random sample of 20 students, 5 are minorities.
II. In a survey about sexual habits, an embarrassed student deliberately gives the wrong answers.
III. A surveyor mistakenly records answers to one question in the wrong space.
14. In a 1927-32 Western Electric Company study on the effect of lighting on worker productivity, productivity increased with each increase in light but then also increased with every decrease in lighting. If it is assumed that the workers knew a study was in progress, what is this an example of?
15. Which of the following are true statements about blocking?
I. Blocking is to experiment design as stratification is to sampling design.
II. By controlling certain variables, blocking can make conclusions more specific.
III. The paired comparison design is a special case of blocking.
16. A new vegetable fertilizer is to be tested at two different levels (regular and double strength) Design an experiment, including a control, for 30 test plots, half of which are in the shade.