For Questions 11-13 use the journal excerpt below:

An epidemiologic study was conducted at a high school to determine if participation in sports were associated with methicillin-resistant Staphylococcus aureus (MRSA) skin infections. The investigators identified 127 laboratory-confirmed MRSA skin infection cases and 381 controls from the high school. Based on review of school records it was determined that among the MRSA cases, 12 were on the wrestling team and only 4 controls were on the wrestling team.

Question 11

What type of study design is this?

• A) Prospective Cohort
• B) Retrospective Cohort
• C) Case-Control
• D) Case Series
• E) None of the above

Question 12

What is the best measure of association, in the above study, to use to examine the exposure disease relationship?

• A) Prevalence
• B) Odds ratio
• C) Risk ratio
• D) Incidence Rate

Question 13

In the study presented above,

how many more times likely were high school students with a MRSA skin infection to be on the wrestling team than students who did not have MRSA? Report your answer rounded to the 10^th decimal place.

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