Statistics A
Chapter 1 Test PRACTICE ANSWERS
Name___________________________
MULTIPLE CHOICE- circle the letter of the correct choice.
1. After inspecting all of 55,000 kg of meat stored at the Wurst Sausage Company, it was found that 45,000 kg of the meat was spoiled. The number “45,000” is a… a) Parameter b) Statistic
2. A health and fitness club surveys 40 randomly selected members and found that the average weight of those questioned is 157 lb. T he number “157” is a… a) Parameter b) Statistic
3. The number of limbs on a 2-year-old oak tree is 21. The number “21” is… a) Discrete b) Continuous
4. The height of 2-year-old maple tree is 28.3 ft. The number “28.3” is… a) Discrete b) Continuous
5. A marketing firm does a survey to find out how many people use a product. Of the one hundred people contacted, fifteen said they use the product. What kind of study is this? a) Observational b) Experimental
6. A quality control specialist compares the output from a machine with a new lubricant to the output of machines with the old lubricant. What kind of study is this? a) Observational b) Experimental
7. A town obtains current employment data by polling 10,000 of its citizens this month. This is an example of which kind of observational study? b) Cross-sectional d) None of these a) Prospective c) Retrospective
8. A pollster uses a computer to generate 500 random numbers, then interviews the voters corresponding to those numbers. This is an example of which kind of sampling? a) Cluster b) Random c) Stratified d) Convenience

9. To avoid working late, a quality control analyst simply inspects the first 100 items produced in a day. This is an example of which kind of sampling? b) Random d) Convenience a) Cluster c) Stratified
10. An education researcher randomly selects 48 middle schools and interviews all the teachers at each school. This is an example of which kind of sampling? a) Cluster c) Stratified b) Random d) Convenience
11. The name of each contestant is written on a separate card, the cards are placed in a bag, and three names are picked from the bag. This is an example of which kind of sampling? a) Cluster c) Stratified b) Random d) Convenience
12. Determine which of the four levels of measurement is most appropriate: Nationalities of survey respondents. a) Nominal c) Interval b) Ordinal d) Ratio
13. Determine which of the four levels of measurement is most appropriate: Ages of survey respondents. a) Nominal c) Interval b) Ordinal d) Ratio
14. Determine which of the four levels of measurement is most appropriate: The subjects in which college students major. a) Nominal c) Interval b) Ordinal d) Ratio
15. Determine which of the four levels of measurement is most appropriate: Student's grades,
A, B, or C, on a test. b) Ordinal d) Ratio a) Nominal c) Interval
16. Determine which of the four levels of measurement is most appropriate: Amount of fat (in grams) in cookies. a) Nominal c) Interval b) Ordinal d) Ratio

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17. At a school there are two different math classes of the same age. The two classes have different teachers. The school principal is interested in gauging the effectiveness of two different teaching methods and asks each teacher to try one of the methods. At the end of the semester both classes are given the same test and the results are compared. In this experiment, what is the variable of interest? Give at least TWO examples of how confounding can occur in this example.
▪ The variable is the effectiveness of teaching methods
▪ Confounding can occur because the classes might have inherent differences in intelligence
▪ Confounding can occur because the classes might have different study habits
▪ Confounding can occur if the classes happen at different times
18. Identify the sample and population. Also, determine whether the sample is likely to be representative of the population: In order to assess the opinion of students about their neurotic football team, a researcher at Michigan interviews a group of ten students walking out of the library.
Sample: 10 students walking out of the library
Population: all Michigan students
Representative of the population? Why or why not? No, too small a sample, and only certain types of students are found at the library
19. A questionnaire is sent to 10,000 persons. 5,000 responded to the questionnaire. 3,000 of the respondents say that they "love chocolate ice cream". We conclude that 60% of people love chocolate ice cream. What is wrong with this survey?
This is a VOLUNTARY RES PONSE SURVEY, so it doesn’t reflect the population as a whole, simply the people who responded.
20. "38% of adults in the United States regularly visit a doctor". This conclusion was reached by a college student after she had questioned 520 randomly selected members of her college. What is wrong with her survey?
The sample was only college students, which is not representative of the population as a whole.
21. A company accused of downsizing workers defended itself with the following statement:
"Yes, we were forced to lay off 20% of our workforce last year, but this year we increased our workforce by 20%, and we therefore now have the same number of employees as before the layoff." What is the flaw in this argument?
The 20% increase did not add back all the workers, it was 20% of a smaller number
(the 20% decrease was 20% of a larger number)

22. A researcher wants to obtain a sample of at least 1000 voters in the city of Portage.
Describe procedures for obtaining a sample of each type: random, systematic, convenience, stratified, cluster.
Random: obtain a list of voters, randomly select 1000
Systematic: obtain a list of voters, select every 10 th voter to get 1000.
Convenience: stand outside Wal-Mart or Meijer, or walk around closest neighborhoods
Stratified: divide voters into age groups (18-29, 30-39, etc), randomly select voters from each group
Cluster: divide voters into precincts (which there are already lots of!), randomly select a few precincts, and select every voter in each chosen precinct
23. A drug company is testing a new miracle weight-loss drug. Early indications suggest that men and women may react differently to treatment. a. Men and women are put into separate BLOCKS (or groups) to test the drug's effect on each gender. b. Half of each group is given the actual treatment while the other half is given a
PLACEBO . c. BLINDING is used so that the subjects don't know who's really receiving the treatment. d. Since the researchers don't even know who's really receiving treatment, DOUBLE -
BLINDING is being used. e. The researchers know there will likely be SAMPLING ERROR arising from chance sample fluctuations.