Chapter Two Questions – Select answer and write out why the answer chosen is correct.
1. Which of the following is a step in the data analysis process?
a. Understanding the nature of the problem
b. Data collection
c. All of these choices.
d. Interpretation of results
2. For which of the following should the six steps to data analysis be used?
a. All of these choices.
b. Planning a study
c. Conducting a study
d. Evaluating a research study
3. What type of bias occurs when the sample selected systematically excludes some part of the
population being studied?
a. Response bias
b. Selection bias
c. Measurement bias
d. Nonresponse bias
4. What term is used when a study collects information from the entire population?
a. Bias
b. Replication
c. Census
d. Sampling
5. Which of the following statements is false?
a. Conclusions about a population are usually based on examination of a sample.
b. A simple random sample from a population gives every sample of size n an equal chance of being
selected.
c. Bias can occur from the way in which a sample is selected.
d. Sampling with replacement includes n distinct individuals from the population.
6. Which of the following is the definition of a sample chosen by cluster sampling?
a. A simple random sample from each of a given number of subpopulations.
b. A sample that is obtained by using an easily available or convenient group.
c. Random selection of one of the first k elements in list, and then the systematic selection of every kth
element thereafter in the population.
d. A simple random sample of clusters from the available clusters in the population.
7. In which of the following does the researcher manipulate one or more factors?
a. an experiment
b. an observational study
c. a census
d. All of these choices.
8. Which of the following statements is true?
a. The goal of an observational study is to determine the effect of the manipulated factors on the
response variable.
b. It is not possible to draw cause-and-effect conclusions from an observational study.
c. In an observational study it is not important to obtain a sample that is representative of the
population.
d. The goal of an experiment is usually to draw conclusions about the population or about differences
between two or more populations.
9. Suppose an employer is interested in taking a sample of 50 employees from all employees who use
the exercise facilities provided at the place of business at least three times a week. What is the sampling
frame?
a. The sampling frame cannot be determined from the information given.
b. The sampling frame consists of all employees at the firm regardless if they use the exercise facilities.
c. The sampling frame consists of all employees at the firm that use the exercise facilities at least three
times a week.
d. The 50 individuals sampled constitute the sampling frame.
10. Which of the following can be used to control extraneous factors in an experiment?
a. Holding the extraneous factors constant
b. All of these choices.
c. Random assignment to experimental groups
d. Blocking
11. What is used to ensure there is an adequate number of observations in each experimental
condition?
a. Confounding
b. Replication
c. Direct control
d. Blocking
12. Three methods for teaching mathematics to first graders are to be compared. Ten students are
randomly assigned to each of the methods, and the score on a quiz is recorded. What are the response
and treatment for this experiment?
a. The students represent the treatments and the response is the number of students for each method.
b. There is not enough information given to answer the question.
c. The three methods are the treatments and the response is the score achieved on the quiz.
d. The treatment is the method and the response is the score they achieve on the quiz.
13. Which of the following is a treatment designed to look like the active treatment but which has no
active ingredients?
a. placebo
b. cluster
c. bias
d. experiment
14. A random sample of fifteen dogs was selected. Their weight and height from the ground to the top
of their back were recorded. The researcher is interested in whether the dog's height accurately predicts
their weight. What are the explanatory variable, the response variable and the experimental units for
this study?
a. The explanatory variable is height, the response variable is the dog, and the experimental units are
the weights.
b. The explanatory variable is weight, the response variable is height, and the experimental units are
the dogs.
c. The explanatory variable is height, the response variable is weight, and the experimental units are the
dogs.
d. The explanatory variable is the dog, the response variable is weight, and the experimental units are
the heights.
15. What type of experiment is conducted when neither the subjects nor the individuals who measure
the response know which treatment was received by the subjects?
a. a volunteer experiment
b. a single-blind experiment
c. a replicated experiment
d. a double-blind experiment
16. A local grocery store surveyed its customers to determine the satisfaction of their shopping
experience (satisfactory, unsatisfactory). What type of variable is being measured?
a. Treatment
b. Quantitative
c. Placebo
d. Categorical
17. Fill in the blank. The effect of a confounding variable on the response variable __________ the
effect of the explanatory variable.
a. cannot be distinguished from
b. equals
c. is larger than
d. can be distinguished from
18. Which of the following statements is correct regarding observational studies?
a. In an observational study, a researcher can minimize but not eliminate the explanatory variables.
b. In an observational study, a researcher can observe but not control the explanatory variables.
c. In an observational study, a researcher can control but not observe the explanatory variables.
d. In an observational study, a researcher can define but not observe the explanatory variables.
19. Suppose a researcher is interested in whether or not the number of years of post high school
education of a person can determine their annual salary. A random sample of 500 people in the United
States was surveyed. What are the response and explanatory variables in this study?
a. The response variable is the number of years of post high school education and the explanatory
variable is annual salary.
b. The response variable is the 500 people surveyed and the explanatory variable is annual salary.
c. The response variable is the annual salary and the explanatory variable is the number of years of post
high school education.
d. The response variable is the 500 people surveyed and the explanatory variable is the number of years
of post high school education.
20. In which of the following sampling methods, is a random sample taken from each subgroup of a
population that is divided into n groups?
a. Cluster sampling
b. Stratified sampling
c. 1 in k systematic sampling
d. All of these choices.
21. What does the term "direct control" mean?
a. Direct control means that extraneous factors are held constant so that their effects are not
confounded with those of the experimental conditions.
b. Direct control means that the assignment of experimental units to treatments or of treatments to
trials is random.
c. Direct control uses extraneous factors to create experimental groups that are similar with respect to
those factors, thereby filtering out their effect.
d. Direct control ensures that there are an adequate number of observations on each experimental
treatment.
22. Which of the following statements is true?
a. It is always reasonable to generalize conclusions from an observational study that used voluntary
response or convenience sampling to a larger population.
b. An observational study can be used to conclude a cause-and-effect relationship.
c. Volunteers as subjects of a study are always representative of the larger population and thus
conclusions from the sample can be made for the population as well.
d. It is reasonable to generalize conclusions based on data from a sample to some population of interest
only when the sample is likely to be representative of the population.
23. Which of the following describes a single-blind experiment?
a. It is an experiment in which the participants do not know which treatment they have been assigned.
b. It is an experiment in which each group receives two treatments (one active and one placebo).
c. It is an experiment in which the control group receives a placebo, which looks like the real treatment
drug but has no active ingredients.
d. It is an experiment in which neither the participants nor the researcher taking the measurements
knows which treatment the participants have been assigned.
24. What type of variable is related both to group membership and to the response variable?
a. a discrete random variable
b. a quantitative variable
c. a confounding variable
d. an extraneous factor
25. When evaluating a study conducted by someone else, what basic principles should you look for in
their study?
a. Direct control
b. Randomization
c. All of these choices.
d. Replication