Which decision is not made during the design of a quantitative study?
a) Which hypotheses should be tested
b) How many times data will be collected
c) Whether there will be an intervention
d) What types of comparisons to make
a) Which hypotheses should be tested
A researcher studying the effects of length of nursing home residency on residents’ emotional well-being compared 100 residents 1 week after admission with 100 residents who had lived in the nursing home for 6 months. This is an example of a:
a) cross-sectional design.
b) longitudinal design.
c) time series design.
d) crossover design.
a) cross-sectional design.
Which feature is not essential for an experimental design?
a) Control
b) Intervention
c) Randomization
d) Blinding
d) Blinding
What does having a control group in a randomized controlled trial allow the researcher to do?
a) Have a benchmark for comparing the experimental group against a group not receiving the experimental intervention
b) Guarantee that the study is rigorous and valid
c) Generalize the results of the experiment to the entire population
d) Reduce research costs by administering a treatment to only half the subjects
a) Have a benchmark for comparing the experimental group against a group not receiving the experimental intervention
Assigning each participant to a group by random assignment means:
a) every participant has an equal chance of being assigned to any group.
b) groups being compared will necessarily be equivalent at the outset.
c) participants are randomly selected from the population.
d) researchers have control over which people are assigned to which groups.
a) every participant has an equal chance of being assigned to any group.
In a crossover design, what type of control group is used?
a) There is no control condition in a crossover design.
b) Subjects are randomly assigned to either a treatment or a no-treatment control group.
c) Control group subjects are exposed to a treatment once and experimental group subjects are exposed repeatedly.
d) Subjects serve as their own controls by being exposed to multiple treatment conditions.
d) Subjects serve as their own controls by being exposed to multiple treatment conditions.
Although crossover designs are powerful, one limitation is the potential problem of:
a) carryover effects.
b) study costs.
c) systematic bias.
d) self-selection.
a) carryover effects.
A researcher studying differences in childbirth outcomes for delivery-table and birth-chair births randomly assigned pregnant women to one of the two groups
and then obtained data on 1-minute Apgar scores. The design used was a:
a) cohort design.
b) crossover design.
c) nonequivalent control group design.
d) posttest-only experimental design.
d) posttest-only experimental design.
A researcher would be best able to draw inferences about cause-and-effect relationships in which study design?
a) Crossover design
b) One-group before-after design
c) Case-control design
d) Time-series design
a) Crossover design
Which research question could be addressed using a true experimental design?
a) What is the effect of cognitive training on the mental health of the elderly?
b) What is the effect of type of obstetric provider (nurse-midwife versus obstetrician) on women’s decision to breastfeed after delivery?
c) What is the effect of nurses’ opportunities for job advancement on their job satisfaction?
d) What is the effect of maternal heroin use on infants’ birth weight?
a) What is the effect of cognitive training on the mental health of the elderly?
What is the difference between a pretest-posttest randomized controlled trial design and a pretest-posttest nonequivalent control group (quasi-experimental)
design?
a) There is no intervention in the nonequivalent control group design.
b) In the experimental design, subjects are assigned to groups at random.
c) The experimental design would be appropriate in laboratory settings and the quasi-experimental design would be appropriate in naturalistic settings.
d) The experimental design involves using subjects as their own controls, but a quasi-experimental design does not.
b) In the experimental design, subjects are assigned to groups at random.
What type of design would be best suited to studying the effect of exposure to cockroach allergens on asthma in children?
a) A nonequivalent control group design
b) A before-after randomized controlled trial design
c) A retrospective case-control design
d) A prospective cohort design
d) A prospective cohort design
A researcher found in a cross-sectional study that people who had experienced more negative life events (e.g., divorce, job loss) had lower scores on a measure of overall physical health than those with few negative life events. The research can conclude:
a) there is a relationship between negative life events and health, but the nature of the relationship is ambiguous.
b) poor physical health led to a higher number of negative life events.
c) characteristics of participants (e.g., their income levels) affected both health and negative life events.
d) negative life events led to deterioration in physical health.
a) there is a relationship between negative life events and health, but the nature of the relationship is ambiguous.
What do matching, randomization, and homogeneity have in common?
a) They are methods of achieving constancy of conditions.
b) They are methods of research control over participants’ characteristics.
c) They are methods that improve the external validity of a study.
d) They are features of experimental design.
b) They are methods of research control over participants’ characteristics.
Why is matching a less desirable research strategy than random assignment?
a) Matching is more costly than randomization.
b) For group comparisons, matching cannot control all confounding subject characteristics, but randomization can.
c) Matching requires a greater level of administrative cooperation than randomization.
d) Matching is not appropriate for most research situations.
b) For group comparisons, matching cannot control all confounding subject characteristics, but randomization can.
A researcher who uses homogeneity as a means of controlling confounding variables pays the price of limiting the studies:
a) feasibility.
b) rigor.
c) internal validity.
d) generalizability.
d) generalizability.
Which control mechanism does not require the researcher to know in advance which participant characteristics need to be controlled?
a) Matching
b) Randomization
c) Homogeneity
d) Statistical control
b) Randomization
Which is not a key aspect of a study’s validity?
a) Implementation validity
b) External validity
c) Statistical conclusion validity
d) Internal validity
a) Implementation validity
In a randomized controlled trial using a pretest-posttest design in which posttest data are collected 6 months after the intervention, the internal validity of the study would most likely be compromised by the:
a) maturation threat.
b) history threat.
c) selection threat.
d) mortality threat.
d) mortality threat.
What is the most salient threat to the internal validity of nonequivalent control group designs?
a) History
b) Selection
c) Mortality
d) Maturation
b) Selection
