Practice Exam

1. Practice Exam Questions 1-5 are based on the following description An advertising firm is conducting a survey of adult South Carolinians about the effectiveness of different advertising campaigns to promote tourism in Florida. Using the most recent voter registration lists, they select a simple random sample of 4,000 registered voters and mail them a survey and $1 (to make people feel more inclined to respond). They send a second reminder envelope (without the $1) to those who hadn’t responded after three weeks. In the end they receive responses from 1,235 people.

2. 1) The sample is: • A) Adult South Carolinians • B) Registered voters in South Carolina • C) The 1,235 people who responded • D) The 2,765 people who did not respond • E) The 4,000 people who received the survey in the mail 

3. 2) The sampling frame is: A) Adult South Carolinians B) Registered voters in South Carolina  C) The 1,235 people who responded D) The 2,765 people who did not respond E) The 4,000 people who received the survey in the mail

4. 3) The error caused by 2,765 people who chose not to send their survey back is: A)A type of nonsampling error caused by nonresponse  B) A type of nonsampling error caused by undercoverage C) A type of sampling error caused by nonresponse D) A type of sampling error caused by undercoverage

5. 4) Imagine that instead of surveying the entire state at once using a single simple random sample, they first broke the state into three regions (the Lowcountry, Midlands, and Upstate) and took a random sample of registered voters from each of those three regions. This would be an example of a: A) Census B) Cluster Sample C) Convenience Sample D) Stratified Random Sample  E) Systematic Sample

6. 5) That people who were more interested in vacationing in Florida were more likely to respond than those who had no interest probably: A) Made the results biased  B) Made the results less variable C) Made the results more variable

7. Questions 6-10 are based on the following description The Pew Research Center recently conducted a survey to see what percentage of American adults say they most admire political leaders who stick to their positions (as opposed to making compromises). The poll was conducted by telephone from September 16-19 and had 1,005 responses from adults with phone lines living in the continental United States. 492 of those responding said they favored leaders who stick to their positions.

8. Ans: D

9. Ans: B

10. 8) The population is: A) American adults  B) Adults with phone lines living in the US C) The 1,005 who responded D) The percentage of American adults who said they favored leaders who stick to their positions E) The percentage of the 1,005 who responded who said they favored leaders who stick to their positions

11. 9) The parameter is: A) American adults B) Adults with phone lines living in the US C) The 1,005 who responded D) The percentage of American adults who said they favored leaders who stick to their positions  E) The percentage of the 1,005 who responded who said they favored leaders who stick to their positions

12. Questions 11-13 are based on the following description A team of researchers wished to study whether oatmeal reduced bad cholesterol levels in those who ate it. They found 500 adults over age 40 who regularly eat oatmeal or products from oatmeal. They then matched each of these 500 with a similar adult (one of the same gender, within 10 pounds of the same weight, and who exercised roughly the same amount) who did not regularly eat oatmeal or products made from oatmeal. Finally, they measured the bad cholesterol LDL for each adult and compared both groups.

13. 11) This is NOT an experiment because: A) It used matched pairs B) It was not at least single-blind C) The researcher did not assign the adults to regularly eat oatmeal or not  D) The researcher did not use randomness E) The sample size wasn’t large enough

14. 12) The individuals in this observational study were: A) The 500 non-oatmeal eaters B) The 500 who regularly ate oatmeal C) The combined 500 oatmeal eaters and 500 non-oatmeal eaters  D) The researchers E) Eating oatmeal and not eating oat-meal

15. Questions 17-23 are based on the following paragraph A team of researchers is attempting to examine the effect of an herbal chewing gum for the prevention of hay-fever symptoms. The researchers select 240 subjects from hay-fever allergy patients at six clinics scattered around the country. The 240 subjects are randomly split into two groups, one receiving the herbal chewing gum, and one receiving a standard chewing gum with the same flavor but none of the active herbal ingredients. Neither the doctors nor the patients know which gum was used in each case. At the end of three weeks the subjects are judged based on their amount of nasal congestion.

16. 17) Explanatory variable(s) in this experiment include: A) Amount of nasal congestion after 3 weeks B) Using herbal chewing-gum and non-herbal chewing gum  C) Whether the patient was also allergic to dust or not D) Two of the above are correct

17. 18) Response variable(s) in this experiment include: A) Amount of nasal congestion after 3 weeks  B) Using herbal chewing-gum and non-herbal chewing gum C) Whether the patient was also allergic to dust or not D) Two of the above are correct

18. 19) That neither the doctors nor the patients know which gum was received in each case makes this study: A) Completely randomized B) Double blind  C) Matched pairs D) Single blind

19. 23) One alternative design would be to divide the subjects into two groups, one with dust allergies and one without dust allergies. Half of those with a dust allergy would be assigned to each treatment, and similarly half of those without a dust allergy would be assigned to each treatment. This would make the study a: A) Block design  B) Completely randomized design C) Matched-pairs design D) Both A and C