AP Stats ch. 4

a sportswriter wants to know how strongly lafl residents suport the local minor league baseball team

a. all residents of lafl

use scenario 4-8. which of the following best describes the inferences the researches can make based in his results?

a. they can make inferences about cause and effect, but not about the populations from which the samples were taken

use scenario 4-8. the experimental units are

b. 100 adult volunteers

3. the sampling frame is

c. all members of the national education association

a double-blind experiment was conducted to evaluate the effectiveness of the salk polio vaccine. the purpose of keeping the diagnoising physicians ignorant of the treatment statsus of the experimental subjects was to..

c. eliminate a polssible source of bias

6. a test is run to compare two calc books, one with a traditional approach and one with a reform approach. a state university agrees to use the traditional text.

c. no because there is a confounding variable: large public university vs. small private

in an experiment, an observed effect so large that it would rarely occur by chance is called

c. statistically significant

20. use scenario 4-7. the brand of pellets is

c. the explanatory variable

under which of the following conditions is it preferable to use stratified rand sampling rather than simple random sampling?

c. the population can be divided into strata so that the individuals in each stratum are as much alike as possible

8. just before the pres election of 1936 the magazine literary digest predicted

c. undercoverage

a.

cluster sample

c.

convenience sampled.

since many individuals walk around their homes in their socks, a manufacturere has reated a material for socks....... the manufacturer wishes to test this belief over a period of a month. given a group of volunteers, which of the following designs will best test this new material's resistance to wear

d. for each volunteer, randomly choose which foot wears a cotton sock, while the other foot wears a sock made of the new material. compare the wear on the socks at the end of the month

spaghetti

d. matched pairs design

telephone poll-takers call near dinner time because most people are at home. this is an effort to avoid

d. nonresponse

we divide the class into two groups; first year students and others. we then take random samples from each group. this is an example of

d. stratified random sampling

10. an author wrote a book that advocated the playing of classical music to little children

e. III and IV

the essential difference between an experiment and an observational study is that

e. an experiment imposes treatments on the subjects, but an observational study does not

the reason that blocking is sometimes used in experimentation is to

e. reduce variability arising from random assignment

7. a pharmacist wants to study the effect of temp on the potency of a headache pain reliever

e. specific temp, pill, relief time

srs

e. systematic sampling

each person in a SRS of 2000 received a survey

e. those who did respond may differ in some important way from those who did not respond

b.

stratified random sample

18 what is wrong with the experimental design?

the type of car is a potential confoudning variable

your school will send a delegation of 35 seniors to a student life convention. 200 girls and 150 boys are eligible to be chosen. if a sample of 20 girls and separate sample 15 boys are each selected randomly, it gives each senoir the same chance to be chosen to attned the convention. is it an SRS

yes, this is an srs. an srs is designed