CBIC Epidemiology 4

Question 1

Which of the following best describes 'confounding' in an epidemiological study of HAIs?

Accepted Answer

A third variable that is associated with both the exposure and the outcome

Answer

Confounding occurs when a third variable is independently associated with both the exposure and the outcome, potentially distorting the true relationship between them.

Question 2

In outbreak investigation, a 'propagated epidemic curve' with successive waves of increasing case counts typically indicates which transmission pattern?

Accepted Answer

Person-to-person spread with progressive secondary cases

Answer

A propagated curve with successive peaks separated by one incubation period indicates person-to-person transmission, where secondary and tertiary cases generate new waves.

Question 3

What is the primary purpose of stratified analysis in HAI epidemiological studies?

Accepted Answer

To identify and control for confounding variables

Answer

Stratified analysis examines the association between exposure and outcome within subgroups defined by potential confounders, allowing assessment and control of confounding effects.

Question 4

A cluster of Legionella cases in a hospital is linked to the cooling tower. Which epidemiological term best describes this type of HAI source?

Accepted Answer

Common vehicle

Answer

A common vehicle refers to a single contaminated source (such as water, food, or equipment) that transmits infection to multiple people, which is the mode for Legionella via cooling towers.

Question 5

Which statistical measure indicates the minimum detectable effect size that a study is powered to identify at a given alpha level?

Accepted Answer

Statistical power

Answer

Statistical power (typically 80% or higher) is the probability of detecting a true effect of a given magnitude; it determines whether a study is adequately sized to identify meaningful differences.

CBIC - Certification Board of Infection Control Practice Test

CBIC - Certification Board of Infection Control Practice Test

CBIC Epidemiology 4