CET Research Methods & Evidence-Based Practice 3 — Questions and Answers
Question 1: Which type of error occurs when a researcher fails to reject a false null hypothesis in an echocardiographic outcome study?
- Type I error (alpha error)
- Type II error (beta error) (Correct answer)
- Sampling error
- Measurement error
Correct answer: Type II error (beta error)
A Type II (beta) error is a false negative — failing to detect a true effect that actually exists.
Question 2: In evaluating interobserver variability of tricuspid annular plane systolic excursion (TAPSE) measurements, which statistic is MOST appropriate?
- Pearson correlation coefficient
- Intraclass correlation coefficient (ICC) (Correct answer)
- Chi-square test
- Odds ratio
Correct answer: Intraclass correlation coefficient (ICC)
The ICC is the preferred statistic for assessing agreement between two or more raters measuring a continuous variable like TAPSE.
Question 3: A case-control study examines whether smoking is associated with aortic root dilation detected on echo. Researchers select 100 patients with dilation and 100 without. What is the key limitation of this design?
- It cannot calculate relative risk directly (Correct answer)
- It requires a long follow-up period
- It is prone to randomization failure
- It cannot assess multiple outcomes
Correct answer: It cannot calculate relative risk directly
Case-control studies calculate odds ratios but cannot directly calculate relative risk because the disease prevalence in the population is not known from the study design.
Question 4: When reviewing a study on strain echocardiography, you notice the authors used p<0.05 as the significance threshold. What does this threshold represent?
- There is a 5% chance the alternative hypothesis is true
- There is a 5% probability of observing the results by chance if the null hypothesis is true (Correct answer)
- The study has 95% power
- 5% of results are clinically significant
Correct answer: There is a 5% probability of observing the results by chance if the null hypothesis is true
A p-value of <0.05 means there is less than a 5% probability of obtaining the observed results if the null hypothesis (no effect) were true.
Question 5: A systematic review on speckle tracking echocardiography uses GRADE criteria to rate evidence quality. Which factor would DOWNGRADE the evidence rating?
- Large effect size
- Consistency across studies
- Serious risk of bias in included studies (Correct answer)
- Dose-response relationship
Correct answer: Serious risk of bias in included studies
Serious risk of bias in included studies is a primary reason to downgrade evidence quality in the GRADE framework.
Question 6: An echocardiography protocol study uses convenience sampling. What is the PRIMARY concern with this approach?
- It increases measurement error
- Results may not be generalizable to the broader population (Correct answer)
- It increases the risk of Type I errors
- It prevents blinding of participants
Correct answer: Results may not be generalizable to the broader population
Convenience sampling selects easily accessible participants, which may not represent the target population and limits external validity.
Question 7: Which component of the PICO framework represents the standard against which a new echocardiographic technique is measured?
- P — Population
- I — Intervention
- C — Comparison (Correct answer)
- O — Outcome
Correct answer: C — Comparison
The 'C' in PICO stands for Comparison, which is the reference standard or alternative intervention being compared to the new technique.
CET Research Methods & Evidence-Based Practice 3
Which type of error occurs when a researcher fails to reject a false null hypothesis in an echocardiographic outcome study?