Question

question 18 (6 points)
question: a city experiences a sudden increase in cases of a rare infectious disease. what study design could be employed to quickly gather information about potential risk factors?

1. case - control
2. cohort
3. cross - sectional
4. ecological

question 19 (6 points)
question: you are working with a medical team to determine how long knee joint prosthesis will last. you review medical records of people who have had to have their prosthesis replaced. what type of study is this?

1. experimental
2. observational
3. ecological

Explanation:

• Question 18: Case - control studies are retrospective. They start with people who have the disease (cases) and a control group without the disease. They then look back at past exposures (risk factors). This is efficient for rare diseases as it doesn't require following a large population over time. Cohort studies (prospective) follow groups over time, which is time - consuming. Cross - sectional studies look at a population at a single time point (not ideal for quickly gathering risk factor info). Ecological studies look at group - level data (not individual risk factors).
• Question 19: Observational studies involve observing and collecting data without interfering. Here, reviewing medical records (no intervention) is observational. Experimental studies involve an intervention (e.g., giving a treatment). Ecological studies focus on group - level data (not individual medical records).

Answer:

1. 1) Case - control
2. 2) Observational