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What is the question asking?How many without disease have a positive test?

How many false positives are expected?

Total without disease TN cases= # False positives

Prevalence = number of people with diseasePeople w/o disease = 1000-(5% * 1000) = 950

Specificity= 75%of people without disease will be TNcasesSpec(TN) cases= .75*950 = 712.5 TN cases

FPcases = 950-712.5= 237 FP cases

The answer is C. 237

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Drug X is investigated in a meta-analysis for itseffect on mortality after a myocardialinfarction. It is found that mortality dropsfrom 10 to 2% when administered. What is theARR?

A. 2%

B. 8%

C. 20%

D. 80%

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ANSWER IS B 8%

ARR = Difference between risk in Exposed

(Exposed Event Rate) vs risk in Control(Control Even Rate)

ARR= CER-EER

10%-2%=8%

The RELATIVE RISK REDUCTION=ARR/

CER= 8%/10%=80%

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How many patients will have to be treated with

drug X to prevent one death? A. 2

B. 8

C. 12.5

D. 50

E. 93

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