MFT Research Methods 3 — Questions and Answers
Question 1: A researcher studying parenting stress recruits participants exclusively from a private therapy practice. Which threat to external validity does this raise?
- History threat
- Selection bias limiting generalizability (Correct answer)
- Instrumentation threat
- Attrition threat
Correct answer: Selection bias limiting generalizability
Recruiting from a non-representative setting limits the ability to generalize findings to broader populations.
Question 2: In an ANOVA, a significant F-ratio tells the researcher that:
- All group means are significantly different from each other
- At least one group mean differs significantly from at least one other (Correct answer)
- The effect size is large
- The null hypothesis is confirmed
Correct answer: At least one group mean differs significantly from at least one other
A significant F only indicates that at least one pair of group means differs; post hoc tests identify which pairs.
Question 3: Which research design would be most appropriate to study changes in family cohesion across adolescence by following the same families over 10 years?
- Cross-sectional design
- Longitudinal design (Correct answer)
- Case-control design
- Single-subject design
Correct answer: Longitudinal design
A longitudinal design tracks the same participants over time, making it ideal for studying developmental change.
Question 4: A researcher uses triangulation in a qualitative study. The primary purpose is to:
- Increase the sample size
- Enhance credibility by using multiple data sources or methods (Correct answer)
- Eliminate researcher bias entirely
- Reduce the cost of data collection
Correct answer: Enhance credibility by using multiple data sources or methods
Triangulation strengthens qualitative trustworthiness by converging evidence from multiple sources, methods, or perspectives.
Question 5: Cohen's d of 0.80 is conventionally interpreted as a:
- Small effect size
- Medium effect size
- Large effect size (Correct answer)
- Negligible effect size
Correct answer: Large effect size
By Cohen's conventions, d = 0.20 is small, 0.50 is medium, and 0.80 or above is large.
Question 6: A researcher studying couple conflict uses a pre-existing observational coding scheme developed for a different population. This raises concerns about:
- Statistical power
- Measurement validity for this population (Correct answer)
- Random assignment
- Demand characteristics
Correct answer: Measurement validity for this population
Applying a coding scheme to a population it was not validated on threatens the measurement validity of the instrument.
Question 7: In a single-subject (N=1) research design, the baseline phase is referred to as the:
- B phase
- A phase (Correct answer)
- Control phase
- Withdrawal phase
Correct answer: A phase
In single-subject ABA designs, 'A' denotes the baseline phase and 'B' denotes the intervention phase.
MFT Research Methods 3
A researcher studying parenting stress recruits participants exclusively from a private therapy practice.
Which threat to external validity does this raise?