CAT 3.2 session nr 3

Which of the following is a measure of the precision of a study's estimate and is often represented by a range of values?

• P-value

• Confidence interval

• Odds ratio

• Sensitivity

Answer explanation

Confidence intervals quantify the precision of study estimates, indicating a range within which the true value is likely to fall.

What is the purpose of randomization in a randomized controlled trial (RCT)?

• To increase external validity

• To ensure blinding of participants

• To eliminate confounding variables

• To reduce the risk of selection bias

Answer explanation

Randomization in RCTs minimizes confounding, ensuring unbiased comparisons between treatment groups and enhancing internal validity.

Which of the following is a measure of association commonly used in cohort studies to quantify the strength of the relationship between an exposure and a disease outcome?

• Odds ratio

• Relative risk

• Hazard ratio

• Confidence interval

Answer explanation

Relative risk in cohort studies gauges the strength of association between exposure and outcome, aiding in causal inference.

In diagnostic studies, what does sensitivity measure?

• The ability of the test to correctly identify individuals without the disease

• The ability of the test to correctly identify individuals with the disease

• The probability of a positive test result given the absence of disease

• The probability of a negative test result given the presence of disease

Answer explanation

Sensitivity reflects the test's ability to correctly identify individuals with the disease, minimizing false negatives.

How does likelihood ratio (LR) contribute to the interpretation of diagnostic test results?

• It provides information about the overall accuracy of the test.

• It helps estimate the probability of having the disease given a positive test result.

• It combines sensitivity and specificity to assess test performance.

• It quantifies how much a test result changes the odds of having the disease.

Answer explanation

Likelihood ratio indicates how much a given test result changes the odds of having the disease, providing valuable information for clinical decision-making.

Sensitivity is the ability of a diagnostic test to correctly identify individuals with the disease, minimizing.............

• True positives

• False negatives

• True negatives

• False positives

Answer explanation

Sensitivity minimizes false negatives by correctly identifying individuals with the disease. False negatives represent cases the test misses, leading to potential underdiagnosis.

Specificity measures the ability of a diagnostic test to correctly identify individuals without the disease, minimizing.........

• True positives

• False negatives

• True negatives

• False positives

Answer explanation

Specificity minimizes false positives by correctly identifying individuals without the disease. False positives are instances where the test incorrectly suggests disease presence, risking overdiagnosis.

With a specificity of 80%, what does Standard Test Y aim to minimize?

• False positives

• False negatives

• True positives

• True negatives

Answer explanation

With a specificity of 80%, Standard Test aims to minimize false positives, indicating its capacity to correctly identify individuals without the Condition.

If a participant has diabetes and Standard Test (HBA1C) misses it, what is this called?

• False positive

• False negative

• True negative

• True positive

Answer explanation

If Standard Test misses the Condition in a person who has it, this is considered a false negative, representing a case where the test fails to detect the true positive.

How would you interpret the finding that Standard Test HBA1C has higher specificity (80%) than Index Test glucometer (75%)?

• Sensitivity is more important than specificity in this context

• Standard Test is more likely to correctly identify individuals without the Condition .

• Index Test is more accurate.

• Both tests are equally reliable.

Answer explanation

The higher specificity of Standard Test suggests it is more likely to correctly identify individuals without the Condition , emphasizing its reliability in ruling out false positives compared to Index Test