AP Statistics – Unit 3 (Chapters 11-13) Warm-Ups

2.	In order to assess the effects of exercise on reducing cholesterol, a researcher sampled 50 people from a local gym who exercised regularly and 50 people from the surrounding community who did not exercise regularly. They each reported to a clinic to have their cholesterol measured. The subjects were unaware of the purpose of the study, and the technician measuring the cholesterol was not aware of whether subjects exercised regularly or not. This is 	
A)	an observational study                  B) an experiment, but not a double-blind experiment	
C)	a double-blind experiment            D) a matched-pairs experiment	

5.	A market research company wishes to find out whether the population of students at a university prefers brand A or brand B of instant coffee. A random sample of students is selected, and each student is asked first to try brand A and then to try brand B, or vice versa (with the order determined at random). They then indicate which brand they prefer. This is an example of 	
A)	an experiment        B) an observational study, not an experiment     C) stratified sampling design     D) block design	

A television station is interested in predicting whether voters in its viewing area are in favor of federal funding for abortions. It asks its viewers to phone in and indicate whether they support/are in favor of or are opposed to this. Of the 2241 viewers who phoned in, 1574 (70.24%) were opposed to federal funding for abortions.
6.	Referring to the information above, the viewers who phoned in are 	
A)	a voluntary response sample      B) a convenience sample     C) a probability sample    D) a population	

7.	Referring to the information above, the sample obtained is 	
A)	a simple random sample      B) a single-stage sample       C) a census      D) probably biased	

8.	In order to assess the opinion of students at the University of Minnesota on campus snow removal, a reporter for the student newspaper interviews the first 12 students he meets who are willing to express their opinion. The method of sampling used is 	
A)	simple random sampling        B) convenience sampling      C) voluntary response     D) a census	

11.	In order to take a sample of 90 members of a local gym, I first divide the members into men and women, and then take a simple random sample of 45 men and a separate simple random sample of 45 women. This is an example of 	
A)	a block design                                                 B) a stratified random sample       	
C)	a double-blind simple random sample            D) a randomized comparative experiment	

12.	A marketing research firm wishes to determine if the adult men in Laramie, Wyoming, would be interested in a new upscale men's clothing store. From a list of all residential addresses in Laramie, the firm selects a simple random sample of 100 and mails a brief questionnaire to each. The population of interest is 	
A)	all adult men in Laramie, Wyoming                      B) all residential addresses in Laramie, Wyoming	
C)	the members of the marketing firm that actually conducted the survey 	
D)	the 100 addresses to which the survey was mailed	

13.	The six people listed below are enrolled in a statistics course taught by means of television. Use the list of random digits           27102 56027 55892 33063 41842 81868 71035 09001 43367 49497 54580 81507 
starting at the beginning of this list, to choose a simple random sample of three to be interviewed in detail about the quality of the course. Use the labels attached to the six names.  The sample you obtain is
1. Moore     2. Casella     3. Santner        4. Goel      5. Jones      6. Klein	

A)	Moore, Casella, Jones            B) 2, 7, 1            C) Moore, Casella, and again Casella	
D)	any set of three names, but we must exclude Casella 	

14.	A public opinion poll in Ohio wants to determine whether registered voters in the state approve of a measure to ban smoking in all public areas. They select a simple random sample of 50 registered voters from each county in the state and ask whether they approve or disapprove of the measure. This is an example of a	
A)	systematic county sample       B) stratified sample      C) multistage sample      D) simple random sample	

16.	A small college has 500 male and 600 female undergraduates. A simple random sample of 50 of the male undergraduates is selected, and, separately, a simple random sample of 60 of the female undergraduates is selected. The two samples are combined to give an overall sample of 110 students. The overall sample is 	
A)	a simple random sample        B) a stratified random sample    C) a multistage sample    D) all of the above	

20.	A 1992 Roper poll found that 22% of Americans say that the Holocaust may not have happened. The actual question asked in the poll was:  Does it seem possible or impossible to you that the Nazi extermination of the Jews never happened?     Twenty-two percent responded “possible.” The results of this poll cannot be trusted because 	
A)	undercoverage is present. Obviously those people who did not survive the Holocaust could not be in the poll	
B)	the question is worded in a confusing manner  	
C)	we do not know who conducted the poll or who paid for the results	
D)	nonresponse is present. Many people will refuse to participate and those that do will be biased in their opinions	

21.	A call-in poll conducted by USA Today concluded that Americans love Donald Trump. USA Today later reported that 5640 of the 7800 calls for the poll came from the offices owned by one man, Cincinnati financier Carl Lindner, who is a friend of Donald Trump. The results of this poll are probably 	
A)	surprising, but reliable since it was conducted by a nationally recognized organization	
B)	biased, but only slightly since the sample size was quite large	
C)	biased understating the popularity of Donald Trump             D) biased overstating the popularity of Donald Trump	

26.	A sociologist wants to study the attitudes of American male college students toward marriage and husband-wife relations. She gives a questionnaire to 25 of the men enrolled in Sociology 101 at her college. All 25 complete and return the questionnaire. The sample in this situation is 	
A)	all men taking a comparable sociology class             B) the 25 men who received and returned the questionnaire	
C)	all the men in the Sociology 101 class                       D) all married men in the Sociology 101 class	

27.	A researcher is interested in the cholesterol levels of adults in the city in which she lives. A free cholesterol screening program is set up in the downtown area during the lunch hour. Individuals can walk in and have their cholesterol levels determined for free. One hundred and seventy three people use the service, and their average cholesterol is 217.8. The sample obtained is an example of 	
A)	a SRS, since the experimenter did not know beforehand which individuals would come to the screening	
B)	a stratified sample of high and low cholesterol individuals	
C)	a sample probably containing bias and undercoverage           D) a multistage sample of varying cholesterol levels	

32.	Which of the following is not a major principle of experimental design? 	
A)	comparative experimentation       B) replication       C) randomization         D) segmenation	

A study of human development showed two types of movies to groups of children. Crackers were available in a bowl, and the investigators compared the number of crackers eaten by children watching the different kinds of movies. One kind of movie was shown at 8 AM (right after the children had breakfast) and another at 11 AM (right before the children had lunch). It was found that during the movie shown at 11 AM, more crackers were eaten than during the movie shown at 8 AM. The investigators concluded that the different types of movies had an effect on appetite. 
33.	The results cannot be trusted because 	
A)	the study was not double-blind. Neither the investigators nor the children should have been aware of which movie was being shown	
B)	the investigators were biased. They knew beforehand what they hoped the study would show	
C)	the investigators should have used several bowls, with crackers randomly placed in each	
D)	the time the movie was shown is a confounding variable	

34.	The response variable in this experiment is 	
A)	the number of crackers eaten     B) the different kinds of movies   C) the time the movie was shown   D) the bowls	

37.	Two variables in a study are said to be confounded if 	
A)	one cannot separate their effects on a response variable           B) they are highly correlated	
C)	they do not have a normal distribution                                      D) one of them is a placebo 	

38.	A study of the effects of running on personality involved 231 male runners who each ran about 20 miles a week. A news report (New York Times, Feb. 15, 1988) stated, “The researchers found statistically significant personality differences between the runners and the 30-year-old male population as a whole.” A headline on the article said, “Research has shown that running can alter one's moods.” Which of the following statements about the study is true? 	
A)	It was not a designed experiment        B) It was an experiment, but not a double-blind experiment	
C)	It was a double-blind experiment, but not a randomized      D) It was a randomized, double-blind experiment	

41.	In a recent study, a random sample of children in grades two through four showed a significant  negative relationship between the amount of homework assigned and student attitudes. This is an example of 	
A)	an experiment                      B) an observational study	
C)	the establishing of a causal relationship through correlation           D) a block design, with grades as blocks	

Researchers wish to determine if a new experimental medication will reduce the symptoms of allergy sufferers without the side effect of drowsiness. To investigate this question, the researchers give the new medication to 50 adult volunteers who suffer from allergies. 44 of these volunteers report a significant reduction in their allergy symptoms without any drowsiness. 
42.	Referring to the information above, this study could be improved by 	
A)	including people who do not suffer from allergies in the study in order to represent a more diverse population	
B)	repeating the study with only the 44 volunteers who reported a significant reduction in their allergy symptoms without any drowsiness, and giving them a higher dosage this time	
C)	using a control group             D) all of the above	

43.	Referring to the information above, the experimental units are 	
A)	the researchers                B) the 50 adult volunteers	
C)	the 44 volunteers who reported a significant reduction in their allergy symptoms without any drowsiness. 	
D)	the six volunteers who did not report a significant reduction in their allergy symptoms without any drowsiness. 	

47.	Will a fluoride mouthwash used after brushing reduce cavities? Twenty sets of twins were used to investigate this question. One member of each set of twins used the mouthwash after each brushing; the other did not.  After six months, the difference in the number of cavities of those using the mouthwash was compared with the number of cavities of those who did not use the mouthwash. This experiment uses 	
A)	random placebos          B) double-blinding        C) double replication      D) a matched-pairs design	

51.	A stratified random sample corresponds to which of the following experimental designs? 	
A)	a block design                             B) a double-blind experiment   	
C)	an experiment with a placebo     D) a confounded, nonrandomized study	

52.	For one kindergarten class in his district, a researcher determines which children already can read simple words and which children cannot upon entering kindergarten. The children are followed until third grade, at which point they are tested to determine the grade level at which they are reading. Those children who were reading simple words on entering kindergarten are found to be reading at a higher level than those who could not read simple words on entering kindergarten. The researcher 	
A)	can conclude that children should be taught to read in preschool, as there are clear benefits to reading early	
B)	cannot conclude that being able to read before entering kindergarten is beneficial, as there may be confounding variables in this study	
C)	needs to have taken a SRS of kindergarten students instead of one class to conclude a cause-and-effect relationship	
D)	needs to retest in sixth grade or no conclusions can be reached	

53.	A basketball player makes 2/3 of his free throws. To simulate a single free throw, which of the following assignments of digits to making a free throw are appropriate? 	
A)	0 and 1 correspond to making the free throw and 2 corresponds to missing the free throw	
B)	01, 02, 03, 04, 05, 06, 07, and 08 correspond to making the free throw and 09, 10, 11, and 12 correspond to missing the free throw	
C)	Both (a) and (b) are correct            D) Neither (a) nor (b) is correct	

To simulate a toss of a coin we let the digits 0, 1, 2, 3, and 4 correspond to a head and the digits 5, 6, 7, 8, and 9 correspond to a tail. Consider the following game: We are going to toss the coin until we either get a head or we get two tails in a row, whichever comes first. If it takes us one toss to get the head we win $2, if it takes us two tosses we win $1, and if we get two tails in a row we win nothing. Use the following sequence of random digits:         12975 13258 45144 
56.	The estimated probability of winning $2 in this game is          57. The estimated probability of winning nothing is	
A)	1/4           B) 5/15             C) 7/11             D) 9/15                        A) 1/2         B) 2/11       C) 6/15     D) 7/11	

58.	The estimated number of tosses in a trial of the game is 	
A)	2.0           B) 15/9                 C) 15/11              D) 11/15	
Answer Key
2.A	5.A	6.A	7.D	8.B	11.B	12.A	13.A	14.B	16.B	20.B	21.D	26.B	27.C
32.D	33.D	34.A	37. A	38. A	41.B	42.C	43.B	51.A	52.B	53.C	56.C	57.B	58.C