1. OnJuly 7, 2010, The Gallup organization conducted a telephone poll of 1,007 random adults in all 50 U.S. states and the District of Columbia. They found that 38% strongly opposed the federal government suing Arizona over their new immigration law. Which is true? I. The population of interest is all U.5. adults. Il. 38% is a statistic and not the actual percentage of all U.S. adults who strongly oppose the lawsuit. lll. This sampling design should provide a reasonably accurate estimate of the actual percentage of all U.S. adults who strongly oppose this lawsuit. a. I, I, and I b.landll c. | only d. Il only 2. A school district has three high schools. The district decides to randomly test high school students for attention deficit disorder (ADD). The school board creates a list of all of the students from the three high schools and randomly samples 250 students from that list. Is this a simple random sample? a. Yes, because students were chosen at random. b. No, because we can't guarantee that there are students from each school in the sample. c. Yes, because this method could choose any 250 high school students from throughout the district. d. No, because we can't guarantee that there are students from each high school grade in the sample. 3. A chemistry professor who teaches a large lecture class gives a survey during class about how he can make the class more interesting. He is hoping he can get more students to attend his class. This survey method suffers from which of the following? a. voluntary response bias b. nonresponse bias c. response bias d. undercoverage Use this information to answer questions 4-7. A statistics teacher wants to know how her students feel about an introductory statistics course. She decides to administer a survey to a random sample of students taking the course. She has several sampling plans to choose from. Name the sampling strategy in each. 4. There are four grade levels of students taking the class: freshmen, sophomores, juniors, and seniors. Randomly select 15 students from each grade level. a. cluster sampling b. simple random sampling c. systematic sampling d. stratified sampling 5. Randomly select a grade level (freshmen, sophomores, juniors, and seniors) and survey every student in that grade level. a. cluster sampling b. simple random sampling c. systematic sampling d. stratified sampling 6. Each student has a nine-digit student number. Randomly choose 60 numbers. a. cluster sampling b. simple random sampling c. systematic sampling d. stratified sampling 7. Using the class roster, select every fifth student from the list. a. cluster sampling b. simple random sampling c. systematic sampling d. stratified sampling _______B. Suppose the state decides to randomly test high school wrestlers for steroid use. There are 16 teams in the league, and each team has 20 wrestlers. State investigators plan to test 32 of these athletes by randomly choosing two wrestlers from each team. Is this a simple random sample? a. Yes, because the wrestlers were chosen at random. b. Yes, because each wrestler is equally likely to be chosen. c. No, because not all possible groups of 32 wrestlers could have been the sample. d. No, because a random sample of teams was not first chosen. 9. Which statement about bias is true? I. Bias results from random variation and will always be present. Il. Bias results from a sampling method likely to produce samples that do not represent the population. lll. Bias is usually reduced when the sample size is larger. a. landlll b. ITand Il c. | only d. Il only ______10. The owner of a car dealership planned to develop strategies to increase sales. He hoped to learn the reasons why many people who visit his car lot do not eventually buy a car from him. For one month he asked his sales staff to keep a list of the names and addresses of everyone who came in to test drive a car. At the end of the month he sent surveys to the people who did not buy a car, asking them why. About one third of them returned the survey, with 44% of those indicating that they found a lower price elsewhere. Which is true? . The population of interest is all potential car buyers. Il. This survey design suffered from non-response bias. lll. Because it comes from a sample 44% is a parameter, not a statistic. a. landll b. ITand Il i d LG and T . none of the above Use this information to answer questions 11-14. Management at a retail store is concerned about the possibility of drug abuse by people who work there. They decide to check on the extent of the problem by having a random sample of the employees undergo a drug test. Several plans for choosing the sample are proposed. Name the sampling strategy in each. 11. Randomly select an employee classification and test all the people who work in that classification - supervisors, full-ime clerks, part-time clerks, and maintenance staff. a. cluster sampling b. systematic sampling c. stratified sampling d. simple random sampling 12. Choose the fourth person that arrives to work for each shift. a. cluster sampling b. systematic sampling c. stratified sampling d. simple random sampling 13. There are four employee classifications: supervisors, full-time clerks, part-time clerks, and maintenance staff. Randomly select ten people from each category. a. cluster sampling b. systematic sampling c. stratified sampling d. simple random sampling 14. Each employee has a three-digit identification number. Randomly choose 40 numbers. a. cluster sampling b. systematic sampling c. stratified sampling d. simple random sampling Use this information to answer guestions 15 19. Researchers who wanted to see if drinking grape juice could help people lower their blood pressure got 120 non-smokers to volunteer for a study. They measured each person's blood pressure and then randomly divided the subjects into two groups. One group drank a glass of grape juice every day while the other did not. After sixty days the researchers measured everyone's blood pressure again. They reported that differences in changes in blood pressure between the groups were not statistically significant. 15. Was this an experiment or an observational study? Explain. a. observational; observed 120 non-smokers b. observational; volunteers caused this study to be biased c. experimental; treatments were applied d. experimental; one group/all non-smokers 16. What is meant by \"not statistically significant\" in this context? a. The differences were large since this lasted 60 days. b. There were not many subjects involved. c. Only non-smokers were included so this could not be expanded to the general population. d. The results were small enough that they could easily be attributed to variability, not the grape juice. 17. Why did the researchers randomly assign the subjects to the groups? a. This equalizes the effects of variables for which were not controlled. b. This was easier. c. They could keep track of who was in which group easier. d. Not everyone liked grape juice. 18. Why did they have a group that was not drinking grape juice? a. They did not like grape juice. b. They needed a control group to compare with the treatment group. c. This was a placebo since they all needed something. d. In order for the experiment to be valid, it needed to be confounded. 19. Why did the researchers study only non-smokers? a. They wanted to limit the number of subjects in the experiments. b. That would result in variability. c. The smokers were used as a control. d. Smoking tends to affect blood pressure. It might have confounded the results. 20. In an experiment the primary purpose of blocking is to reduce : a. bias b. randomness C. variation d. undercoverage 21. More dogs are being diagnosed with thyroid problems than have been diagnosed in the past. A researcher identified 50 puppies without thyroid problems and kept records of their diets for several years to see if any developed thyroid problems. This is a(n) a. prospective study b. retrospective study c. randomized experiment d. survey 22. Which of the following is not required in an experimental design? a. control b. replication c. randomization d. blocking 23. A headline in a local newspaper announced \"Video game playing can lead to better spatial reasoning abiliies.\" The article reported that a study found \"statistically significant differences\" between teens who play video games and teens who do not, with teens who play video games testing better in spatial reasoning. Do you think the headline was appropriate? Explain. a. No, there was no control group. b. No, this is an observational study which cannot imply causation. c. Yes, there was a statistically significant difference. d. Yes, there were two groups, one of which was a control group. 24. In an experiment, a placebo is used to a. speed the rate of the experiment b. eliminate confounding c. assist in blinding d. increase blocking 25. A researcher wants to compare the performance of three types of pain relievers in volunteers suffering from arthritis. Because people of different ages may suffer arthritis of varying degrees of severity, the subjects are split into two groups: under 60 and over 60. Subjects in each group are randomly assigned to take one of the medications. Twenty minutes later they rate their levels of pain. This experiment a. is completely randomized b. has one factor (medication) blocked by age c. has two factors, medication and age d. has one factor (age) blocked by medication type 26. Can watching a movie temporarily raise your pulse rate? Researchers have 50 volunteers check their pulse rates. Then they watch an action film, after which they take check their pulse rates once more. Which aspect of experimentation is present in this research? a. a placebo b. blinding c. randomization d. none of these Use the following information to answer questions 27 30. A study was created to test the effects of jazz on people's sleep patterns. The hypothesis of the experiment was that if people listened to jazz music as they fall asleep, they will sleep for longer periods of time. For the experiment, 2 groups of people were created. One group was placed in a quiet room where they went to sleep and they were timed on how long they slept. The other group was placed in a room where jazz music played softly as they began to sleep and played throughout the night. As each group awoke, their sleep times were monitored. 27. What is the factor in this case? a. sleep patterns b. sleep times c. jJazz played d. 2 groups of people 28. What is the response variable? a. jazz played b. sleep times c. 2 groups of people d. quiet room 29. What is the control group? a. The group with no jazz while sleeping. b. The group listening to jazz. c. The group that was given placebos. d. The group that was blinded. 30. What is the experimental group? a. The group in the experiment. b. The group in the quiet room. c. The group that was given placebos. d. The group who listened to jazz while sleeping. ____31. What control was used in this experiment? Shortly after Ms. Berndt's cat, Revere, was born, Ms. Berndt realized Revere wasn't eating enough. She went to the pet store and bought many different kinds of food and fed Revere different types every day. Each day she noted the type of food and how much Revere ate out of his dish. Eventually Revere ate a lot of the CreppyCat brand food and Ms. Berndt bought that for him from then on. Revere is the best worst cat ever. a. Revere was not eating cat food. b. CreppyCat brand food. c. Many different kinds of food. d. There is no control group. 32. It's a common belief that people behave strangely when there's a full moon and that as a result police and emergency rooms are busier than usual. If you wanted to find out whether there is any value to this belief, what kind of study would you use and why? a. experiment; use as a control, those days when there is no full moon b. experiment; use blinding and don't tell anyone what you are looking for c. prospective observational study; find out which days are full moon days and talk with officers and emergency room personnel d. retrospective observational study; it is easier to go back three years to find data to support this belief ___33. Aswimsuit manufacturer wants to test the speed of its newly designed swimsuit. The company designs an experiment by having 6 randomly selected Olympic swimmers swim as fast as they can in their old suits first, and then swim the event again with the new, expensive swimsuit. The company will use the difference in times as the response variable. Which of the following is present in this experiment? a. blinding b. an explanatory variable c. blocking d. a placebo 34, Before drilling for water, many rural homeowners hire a dowser (a person who claims to sense the presence of underground water using a forked stick). Suppose we wish to set up an experiment to test one dowser's ability. We get 20 identical containers, fill some with water, and ask him to identify which containers have water. The dowser correctly identifies the contents of 11 out of 20 containers. Is this level of success statistically significant? Explain. a. no, he needs to replicate the experiment b. no, 55% (11/20) is not much better than 50% (10/20) c. yes, that is better than the mean d. yes, anything above 0% is great 35. Which of the following studies is experimental? a. Incidences of cancer in people who lived near a chemical factory are compared to those who did not live near this factory. b. The weights of school athletes and non-athletes are compared. c. A survey examines if doctors with different specialties have different stress levels. d. Similar patients with high blood pressure are randomly given three different doses of a new drug and their blood pressure is cbserved. 36. In an experiment the primary purpose of blinding is to reduce : a. randomness b. variation c. bias d. confounding 37. In an experiment the primary purpose of blocking is to reduce a. bias b. randomness c. factors d. variation 38. In an experiment, the best way to reduce confounding is to use . a. a placebo b. a control group c. randomization d. a response variable 39. You want to compare the average ages of the math and science teachers at your local high school. Which is the best method to collect the data? a. sample survey b. census c. simulation d. observational study _____40. Among a dozen eggs, three are rotten. A recipe calls for two eggs; they'll be selected randomly from the dozen. Which plan could be used to simulate the number of rotten eggs that might be chosen? I.Let 0, 1, and 2 represent the rotten eggs; 3, 4, 5, 6, 7, 8, 9, 10, and 11 represent the good eggs. Generate two random numbers 0-11, ignoring repeats. Il. Randomly generate a 0, 1, or 2 to represent the number of rotten eggs you get. lll. Since 25% of the eggs are rotten, let 0 = rotten and 1, 2, 3 = good. Generate two random numbers 0-3 and see how many 0's you get. a. I b. 1l c.l d. I and Il only 41. Hannah wants to simulate whether customers will choose a small, medium, or large drink, or no drink at a fast food restaurant. She decides to use digits from a random number table to represent the drink option a customer will order (0=no drink, 1=small drink, 2=medium drink, 3=large drink, ignore digits 4-9) Why does this NOT model the situation? a. The choices are not equally likely to occur. b. Some of the digits were ignored. c. The choice are independent of each other. d. Some customers had more than one drink. 42. Does donating blood lower cholesterol levels? 50 volunteers have a cholesterol test, then donate blood, and then have another cholesterol test. Which aspect of experimental design is present? a. blocking b. randomization c. blinding d. none of these 43. In a simulation of a couple who is willing to have as many children as necessary to have two girls, how could you assign digits to estimate the average number of children required to have two girls? a. Assign the even digits 0, 2, 4, 6, 8 to boys and the odd digits 1, 3, 5, 7, 9 to girls. b. Assign digits 0-5 to girls and 6-9 to boys. c. Assign digits 00-50 to girls and 51-99 to boys. d. Assign digits 1-50 to girls and 51-99 to boys. Use this information to answer questions 44 46. The Mars candy company starts a marketing campaign that puts a plastic game piece in each bag of M&Ms. 25% of the pieces show the letter \"M", 10% show the symbol \"&", and the rest just say \"Try again\". When you collect a set of three symbols \"M", "&", and "M" you can turn then in for a free bag of candy. Below is the information obtained from the simulation for the 2 trials. 69074 91976 33584 94138 87637 _ 48324 77938 31249 64710 02295 44, How could you assign random numbers to estimate the average number of bags a consumer would have to buy to get a free one? a. Assign 0-9 to pieces with \"M", 10-13 to pieces with \"&", and 14-39 to pieces with \"Try again\". b. Assign 00-24 to pieces with "M", 25-34 to pieces with \"&", and 35-99 to pieces with \"Try again\". c. Assign 00-24 to pieces with \"M" and 25-99 to all other pieces. d. none of these 45. Assume that you chose the correct assignment of random numbers in Q44, what are your outcomes for Trial 1 and Trial 27 a. Trial 1 outcome = 6, and Trial 2 outcome =7 b. Trial 1 outcome = 9, and Trial 2 outcome = 7 c. Trial 1 outcome = 7, and Trial 2 outcome = 6 d. Trial 1 outcome = 6, and Trial 2 outcome = 10 46. About how many bags will a consumer have to buy to get a free one? a. average 7.5 bags b. average 6.5 bags c. average 8 bags d. average 7 bags 47, Your state's BigBucks Lottery prize has reached $100,000,000, and you decide to play. You have to pick five numbers between 1 and 60, and you'll win if your numbers match those drawn by the state. You decide to pick your \"lucky\" numbers using a random number table. Which numbers do you play, based on these random digits? 43680 98750 13092 76561 58712 a. 43, 9,50, 13, 27/ b. 43, 68, 9, 87, 50 c.4,3,68,0 d. 43, 98, 13, 76, 58 Use this information to answer guestions 48 50. You take a quiz with & multiple choice questions. After you studied, you estimated that you would have about an 80% chance of getting any individual guestion right. Below is the information obtained from the simulation for the 7 trials. : 48. How would you use the random digits to represent the B0% chance that you get the answer right? a. none of these b. Assign random digits 0-10. Let 0-7 = right and 8-10 = wrong. c. Assign random digits 0-9. Let 0-6 = right and 7-9 = wrong. d. Assign random digits 0-9. Let 0-7 = right and 8-9 = wrong. 49. Assume that you chose the correct assignment of random digits in Q48, out of the 7 trials, how many trial outcomes did you get all 6 questions right? R LA oW H 50. What are your chances of getting all 6 right? Based on the outcomes of the 7 trials. a. about 57% b. about 43% c. about 75% d. about 25%