1. Ann Landers, who wrote a daily advice column appearing across the country, once, asked her readers, \"if you had it to do over again, would you have children?\" Of more than 10,000 readers who responded, 70% said no. What does this show? (A) The survey is meaningless because of voluntary response bias. (B) No meaningful conclusion is possible without knowing something more about the characteristics of her readers. (C) The survey would have been more meaningful if she had picked a random sample of the 10,000 readers who responded. (D) The survey would have been more meaningful if she had used a control group. (E) This was a legitimate sample, randomly drawn 'om her readers and of sufcient size to allow the conclusion that most of her readers who are parents would have second thoughts about having children. 2. Which of the following are true statements? I. If bias is present in a sampling procedure, it can be overcome by dramatically increasing the sample size. II. There is no such thing as a \"bad sample\". III. Sampling techniques that use probability techniques effectively eliminate bias. (A)I only (B) II only (C) III only (D) None of the statements are true. (E) None of the above gives the complete set of true responses. 3. Two possible wordings for a questionnaire on gun control are as follows: I. The United States has the highest rate of murder by handguns among all countries. Most of these murders are known to be crimes of passion or crimes provoked by anger among acquaintances. Are you in favor of a 7-day cooling off period between the lling of an application to purchase a handgun and the resulting sale? 11. The United States has the highest rate of murder by hand guns among all countries. Many people want to keep handguns in their homes for self-protection. Fortunately, U.S citizens are guaranteed the right to bear arms by the constitution. Are you in favour of a 7-day cooling off period between the lling of an application to purchase a need a handgun and the resulting sale? One of these questions showed that 25% of the population favored a 7-day waiting period between application for purchase of a handgun and the resulting sale, while the other question showed that 70% of the population favored the waiting period. Which produced which result and why? CAT 2 by Prof. Levi Mbugua (A) The rst question probably showed 25% and the second question 70% because of placebo effect due to the wording of the questions. (B) The rst question probably showed 25% and the second question 70% because of lack of a control group. (C) The rst question probably showed 25% and the second question 70% because of response bias due to the wording of the question. (D) The rst question probably showed 70% and the second question 25% because of response bias due to the wording of the question. 4. Which of the following are true statements? I. Voluntary response samples often under represent people with strong opinions. H. Convenience samples often lead to under coverage bias. III. Questionnaires with nonneutral wording are likely to have response bias. (A) I and H (B) I and HI (C) 11 and HI (D) I, H and HI (E) None of the above gives a complete set of true responses. 5. Each of the 29 NBA team players. A sample of 58 players is to be chosen as follows. Each team will be asked to place 12 cards with their players' names into a hat and randomly draw out two names. The two names from each team will be combined to make up the sample. Will this method results into a simple random sample of 348 basketball players? (A) Yes, because each player has the same basketball player. (B) Yes, because each team is equally represented. (C) Yes, because this is an example of stratied sampling, which is a special case of simple random sampling. (D) No, because the teams are not chosen randomly. (E) No, because not every group of 58 players has the same chance of being selected. 6. To survey the opinions of bleacher fans at Wrigley Field, a surveyor plan to select every one hundredth fan entering the bleachers one afternoon. Will this result in a simple random of club fans who sits 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 bleachers. (C) Yes, because the 99 out of 100 bleachers 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 simple random sampling. (E) No, because not every sample of the intended size has an equal chance of being selected 7. Which of the following are true statements about sampling error? 1. Sampling error can be eliminated only if a surveyor is both extremely well designed and extremely well conducted. 11. Sampling error concerns natural variation between samples, is always present, and can be described using probability. CAT 2 by Prof. Levi Mbugua HI. Sampling error is generally smaller when the sample size is larger. (A) I and H (B) I and HI (C) II and 111 (D) I, H and III (E) None of the above gives the complete set of true responses. 8. What fault do all these sampling designs have in common? I. The wall street journal plans to makes prediction for the presidential election based on a survey of its readers. II. A radio talk show asks people to phone in their views on whether the United States should pay off its huge debt of the United Nations. III. A police detective, interested in determining the extent of drug use by teenagers, randomly picks a sample of high school students and interviews each one about any illegal drug use by students during the past year. (A) All the designs make improper use of stratication. (B) All of the designs have errors that can lead to strong bias. (C) All the designs confuse association with cause and reect. (D) None of the designs satisfactorily controls for sampling error. (E) None of the designs makes use of chance in selecting a sample. 9. A state auditor is given an assignment to choose and audit 26 companies. She lists all companies whose names begin with A, assigns each a number, and uses a random number table to pick one of these numbers and thus one company. She proceeds to use the same procedure for each letter of the alphabet and then combines the 26 result into a group for auditing. Which of the following are true statements? 1. Her procedure makes use of chance. II. Her procedure results in a simple random sample. HI. Each company has an equal probability of being selected. (A) I and H (B) I and HI (C) I, H and HI (D) None of the above gives the complete set of true responses. 10. A researcher planning a survey of heads of households in a particular state has census list for each of the 23 counties in that state. The procedure will be to obtain a random sample of heads of households from each of the counties rather than grouping the entire census list together and obtaining a sample om the entire group. Which of the following is a true statement about the resulting stratied sample? I. It is not a simple random sample. II. It is easier and less costly to obtain than a simple random sample HI. It gives comparative information that a simple random sample would not give. (A) I only (B) I and H (C) I and HI CAT 2 by Prof. Levi Mbugua (D) I, H and HI (E) None of the above gives the complete set of true responses. 11 To nd the average occupancy size of student-rented apartments, a researcher picks a simple random sample of 100 such apartments. Even aer one follow-up, the interviewer is unable to make contact with anyone in 27 of these apartments. Concerned about non response bias, the researcher chooses another simple random sample and instructs the interviewer to continue this procedure until contact is made with someone in a total of 100 apartments. The average occupancy size in the nal 100- apartment sample is 2.78. This estimates probably too high or too low? (A) Too low, because of under coverage bias. (B) Too low, because of convenience sample overestimate average result (C) Too high, because of under coverage bias (D) Too high, because convenience sample overestimate average sample (E) Too high, because voluntary response sample overestimates average result. 12. To conduct a survey of long distance calling patterns, a researcher opens a telephone book to a random page, closes his eyes, puts his gure down on the page, and then reads off the next 50 names. Which of the following are true statements? I. The survey incorporates chance. II. The procedure results in a simple random sample. 111. The procedure could easily result in selection bias. (A) I and H (B) I and IH (C) II and III (D) I, H and III (E) None of the above gives the complete set of true responses. 12. To conduct a survey of long distance calling patterns, a researcher opens a telephone book to a random page, closes his eyes, puts his gure down on the page, and then reads off the next 50 names. Which of the following are true statements? I. The survey incorporates chance. H. The procedure results in a simple random sample. III. The procedure could easily result in selection bias. (A) I and H (B) I and HI (C) H and IH (D) I, H and 1H (E) None of the above gives the complete set of true responses. 13. Which of the following are true statements about sampling? 1. Careful analysis of a given sample will indicate whether or not it is random H. Sampling error implies an error, possibly very small but still an error, on the part of the surveyor HI. Data obtained while conducting a census are always more accurate than obtained om a sample, no matter how careful the design of the sample. (A) I only (B) H only (C) III only (D) None of these statements are true. (E) None of the above gives the complete set of true responses. 14. Consider the following three events: 1. Although 18% of the student body is minorities, in a random sample of 20 students, 5 are minorities. H. In a survey about sexual habits, an embarrassed student deliberately gives the wrong answers. HI. A surveyor mistakenly records answers to one question in the wrong space. Which of the following correctly characterizes the above? CAT 2 by Prof. Levi Mbugua (A) 1, sample error; H, response bias; HI, human mistake (B) I, sampling error; H, non-response bias; HI, hidden error (C) 1, hidden bias; H voluntary sample bias; HI, sampling error (D) I, under coverage error, H, voluntary error; HI unintentional error (E) 1, small sample error; H, deliberate error; HI, mistaken error. 15. A researcher plans a study to examine the depth of belief in God among the adult population. He obtains a simple random sample of 100 adults as they leave church one Sunday morning. All but one of them agrees to participate in survey. Which of the following are true statements? I. proper use of chance as evidenced by the simple random sample makes this a well- designed survey II. The high response rate makes this a well- designed survey. HI. Selection bias makes this a poorly designed survey (A) I only (B) H only (C) III only (D) I and H (E) None of these statements is true