Definitions
(32) A critical difference between experiments and observational studies is
A. an experiment often suggests a causal relationship, whereas an observational study only suggests an association.
B. observational studies make use of randomization, whereas experiments do not.
C. experiments are generally more cost and time effective than observational studies.
D. tests of significance can be sued on data collected from experiments but not on data from observational studies.
E. experiments are free to choose subjects from an entire population, whereas an observational study only considers a random sample.
A. an experiment often suggests a causal relationship, whereas an observational study only suggests an association.
(28) Which of the following statement is incorrect?
A. Voluntary response samples often underrepresent people with strong opinions.
B. Convenience samples often lead to undercoverage bias.
C. Questionnaires with non-neutral wording are likely to have response bias.
D. There is no way to fix the results if a biased sampling method was employed.
E. Nonresponse bias should be avoided because those who do not respond might have different views from those who do respond.
A. Voluntary response samples often underrepresent people with strong opinions.
(4) Two studies are run to compare the experience of low-income families receiving food stamps to those receiving cash subsidies. The first study interviews 50 families who have been in each government program for at least 2 years, while the second randomly assigns 50 families to each program and interviews them after 2 years. Which of the following is a true statement?
A. Both studies are observational studies because of the time period involved. B. Both studies are observational studies because there are no control groups.
C. The first study is an observational study; the second is an experiment.
D. The first study is an experiment; the second is an observational study.
E. Both studies are experiments, because in each, families are receiving treatments (food stamps or cash).
C. The first study is an observational study; the second is an experiment.
(42) A candy manufacturer wants to test consistency of the sugar content of chocolate-covered cherries produced in one factory. The company decides to randomly select three boxes of chocolate-covered cherries from each day's production run at the factory and analyze every cherry in each of these bozes as to sugar content. What type of sampling is this?
A. Cluster
B. Convenience
C. Simple random
D. Stratified
E. Systematic
A. Cluster
(8) Which of the following is most useful in establishing cause-and-effect relationships?
A. A complete census
B. A least squares regression line showing high correlation
C. A simple random sample (SRS)
D. A well-designed, well-conducted survey incorporating chance to ensure a representative sample
E. A controlled experiment
E. A controlled experiment
(20) What is bias in conducting surveys?
A. An example of sampling error
B. Lack of a control group
C. Confounding variables
D. Difficulty in concluding cause and effect
E. A tendency to favor the selection of certain members of a population.
E. A tendency to favor the selection of certain members of a population.
(40) Which of the following statements about sampling error is incorrect?
A. Sampling error can be eliminated only if a survey is both extremely well designed and extremely well conducted.
B. Sampling error concerns natural variation between samples, is always present, and can be described using probability.
C. Sampling error is generally smaller when the sample size is larger.
D. Sampling error is unrelated to bias.
E. Sampling error is greater when working with higher confidence levels.
A. Sampling error can be eliminated only if a survey is both extremely well designed and extremely well conducted.
(30) A consumer product agency tests kilowatts per hour for a sample of refrigerators, each one of three different sizes. Which of the following is true?
A. There are three explanatory variables and one response variable.
B. There is one explanatory variable with three levels of response.
C. Kilowatts per hour is the only explanatory variable, but there are three response variables corresponding to the different sizes.
D. There are three levels of a single explanatory variable.
E. Each explanatory level has an associated level of response.
D. There are three levels of a single explanatory variable.
(21) A human resources department plans to survey 100 of the 3,000 employees in the firm. An alphabetical list of the employees is available, a random number between 1 and 30 is picked and the sample consists of the person that far down the list together with every 30th person after that. This procedure is an example of which type of sampling?
A. Cluster
B. Convenience
C. Simple Random
D. Stratified
E. Systematic
E. Systematic
(13) Which of the following is most important in minimizing the placebo effect?
A. Replication and randomization
B. Replication and blinding
C. Randomization and blinding
D. Randomization and a control
E. Blinding and a control
E. Blinding and a control
(2) An advantage to using surveys as opposed to experiments is that
A. surveys are generally cheaper to conduct.
B. it is generally easier to conclude cause and effect from surveys.
C. surveys are generally not subject to bias.
D. surveys involve use of randomization.
E. surveys can make use of stratification.
A. surveys are generally cheaper to conduct.
(23) To conduct a survey on holiday shopping patterns, a researcher opens a telephone book to a random page, clsoes his eyes, puts his finger down on the page, and then reads off the next 100 names. Which of the following is not a true statement?
A. The survey incorporates chance.
B. The procedure results in a systematic sample.
C. The procedure could easily result in selection bias.
D. The procedure is not a simple random sample.
E. The use of a phone book will result in under coverage bias.
B. The procedure results in a systematic sample.
(41) A researcher plans a study to examine the depth of belief in alternative, nontraditional health procedures among the adult population. She obtains a simple random sample of 100 adults leaving an acupuncture/herbal medicine healther center one morning. All but one of them agree to participate in the survey, consisting of a series of neutrally worded questions. Which of the following is a true statement?
A. Proper use of chance as evidenced by the simple random sample makes this a well-designed survey.
B. The high response rate makes this a well-designed survey.
C. Use of neutral wording makes this a well-designed survey.
D. The large sample size makes this a well-designed survey.
E. Selection bias makes this a poorly designed survey.
E. Selection bias makes this a poorly designed survey.
(43) A town has one high school, which buses students from urban, suburdan, and rural communities. Which of the following sampling techniques is most recommended in studying attitudes toward military enlistment after high school graduation?
A. Cluster Sample
B. Simple Random Sample
C. Stratified Sample
D. Systematic Sample
C. Voluntary Response Sample
C. Stratified Sample
(14) In general, for a survey to yield usable results:
A. A sample size of n = 30 is usually sufficient.
B. Researchers must be careful in the way questions are worded.
C. Researchers must carefully choose people who they think are representative of the population.
D. A census is the only truly accurate methodology
E. Sampling error must be avoided.
B. Researchers must be careful in the way questions are worded.
(48) Sampling error is
A. the mean of a sample statistic.
B. the standard deviation of a sample statistic.
C. the standard error a sample statistic.
D. the result of bias.
E. the difference between a population parameter and an estimate of that parameter.
E. the difference between a population parameter and an estimate of that parameter.
(44) Which of the following statement is incorrect?
A. Based on careful use of control groups and random assignment, experiments can often indicate cause-and-effect relationships.
B. Although observational studies may suggest relationships, it would be very difficult to conclude cause and effect because of the lack of control over confounding variables.
C. A complete census is the only way to absolutely establish a cause-and-effect relationship.
D. In order to generalize from samples to the populations they come from, the samples should be selected at random from the populations.
E. When treatments are applied to randomly formed groups, cause-and-effect conclusions become possible.
C. A complete census is the only way to absolutely establish a cause-and-effect relationship.
(5) A food judge is given an assignment to choose and sample the food at 52 (out of over 20,000) NYC restaurants. She has an assistant list all restaurants whose name begins with A, assigns each a number, and uses a random number generator to pick two of these numbers and thus two restaurants. She proceeds to use the same procedure for each letter of the alphabet and combines the results into a group of 52. Which of the following is a true statement?
A. Her procedure makes use of chance.
B. Her procedure results in a simple random sample.
C. Each restaurant in NYC has an equal probability of being selected.
D. The restaurant Moosewood probably has a higher probability of being selected than the restaurant Xander.
E. This is an example of a systematic sample.
A. Her procedure makes use of chance.
(3) A company wishes to survey what people think about a new product it plans to market. They decide to randomly sample from their customer database as this includes phone numbers and addresses. This procedure is an example of which type of sampling?
A. Cluster
B. Convenience
C. Simple Random
D. Stratified
E. Systematic
B. Convenience
(7) Fifty migraine patients are randomly selected from hospital records. Half the patients are told to drink ice water and sit in the dark when they next experience a migraine; the remaining patients are told to use neither of these possible remedies. Participants then report back as to relief, if any. Faults of this experimental design include all of the following except:
A. Lack of randomization
B. Confounding variables
C. Lack of blinding
D. Unclear factor levels.
E. Measurement of response variable
C. Lack of blinding
(12) Sampling error occurs _
A. when interviewers make mistakes resulting in bias.
B. when interviewers use judgment instead of random choice in picking the sample.
C. when samples are too small.
D. because a sample statistic is used to estimate a population parameter.
E. in all of the above cases.
D. because a sample statistic is used to estimate a population parameter.
(11) A researcher planning a survey of heads of households in New York has census lists for each of the 62 counties in the state. The procedure will be to obtain a simple random sample of heads of households from each of the counties rather than grouping all the census lists together and obtaining a sample from the entire group. Which of the following is not a true statement about the resulting stratified sample?
A. It is more susceptible to bias than would be a simple random sample.
B. It is easier and more cost effective than a simple random sample.
C. It gives comparative information that a simple random sample wouldn't give.
D. It recognizes that opinions of heads of households in rural NY communities may differ from those in urban communities.
E. All the above are true statements.
A. It is more susceptible to bias than would be a simple random sample.
(46) A study is made on whether or not a particular review book helps students achieve higher scores on the AP Statistics exam. In comparing records of 100, half of whom purchased the review book, it is noted that the average AP Stat score is higher for those 50 students who purchased the book. Which of the following are true statements?
I. While this study indicates a relation, it does not prove causation.
II. There could well be a lurking variable responsible for the seeming relationship.
III. Self-selection here makes drawing a conclusion difficult.
A. I and II
B. I and III
C. II and III
D. I, II, III
E. None of the above gives the complete set of true responses.
D. I, II, III
I. While this study indicates a relation, it does not prove causation.
II. There could well be a lurking variable responsible for the seeming relationship.
III. Self-selection here makes drawing a conclusion difficult.
(39) Suppose you wish to compare the average height of math/science teachers to the average height of English/social studies teachers in your high school. Which is the most appropriate technique for gathering the needed data?
A. Census
B. Sample survey
C. Experiment
D. Observational study
E. None of these methods is appropriate
A. Census
(37) In which of the following studies could a cause-and-effect (rather than simple association) conclusion probably be reasonable?
A. Studies noting heights and ages at death tend to show that taller people live longer than shorter people.
B. Studies noting that children born prematurely tend to engage in less risky behaviors as adults.
C. Studies showing that animals fed low-calorie diets tend to live longer than animals on normal diets.
D. Studies showing that drivers who do not use seat belts have higher mortality rates in accidents than those who do use seat belts.
E. Studies that show that students who regularly binge drink have lower GPAs than students who don't.
C. Studies showing that animals fed low-calorie diets tend to live longer than animals on normal diets.