Stats

Question 1

What is absolute risk reduction?

Answer 1

The absolute risk reduction is the decrease in risk of a given activity or treatment in relation to a control activity or treatment. It is the inverse of the number needed to treat.

Question 2

What is the equation of absolute risk reduction?

Answer 2

A% - B%

Question 3

What is relative risk?

Answer 3

Relative risk (RR) is the ratio of risk in the experimental group (experimental event rate, EER) to risk in the control group (control event rate, CER)

Question 4

What is the equation of relative risk?

Answer 4

e.g.

Experimental event rate, EER = 10 / 100 = 0.10

Control event rate, CER = 50 / 300 = 0.166

Therefore the relative risk = EER / CER = 0.1 / 0.166 = 0.6

Question 5

What is the equation for sensitivity?

Answer 5

True P / (True P + FN )

Question 6

What is the equation for specificity?

Answer 6

True N / (True N + FP)

Question 7

What is the equation for positive predictive value?

Answer 7

True P / (True P + FP)

Question 8

What is the equation for negative predictive value?

Answer 8

True N / (True N + FN)

Question 9

What is the equation for likelihood ratio for a positive test result?

Answer 9

sensitivity / (1 - specificity)

Question 10

What does likelihood ratio for a positive test result mean?

Answer 10

How much the odds of the disease increase when a test is positive

Question 11

What does likelihood ratio for a negative test result mean?

Answer 11

How much the odds of the disease decrease when a test is negative

Question 12

What is the equation for likelihood ratio for a negative test result?

Answer 12

(1 - sensitivity) / specificity

Question 13

What is equivalent to the pre-test probability?

Answer 13

Prevalence