Ethics & Statistics

Question 1

How do you calculate sensitivity?

Answer 1

Sensitivity = (True positives)/(true positives + false negatives)
= ability to identify people who truly has the disease

Question 2

How do you calculate specificity?

Answer 2

Specificity = (True negatives)/(true negatives + false positives)

Question 3

What is the definition of positive predictive value?

-calculation?

Answer 3

Probability that a person has the disease if the test is positive
= (true positives)/(true positives + false positives)

Question 4

What is the definition of negative predictive value?

-calculation?

Answer 4

Probability that a person does not have the disease if the test is negative
= (true negatives)/(true negatives + false negatives)

Question 5

What is the definition of relative risk?

-what is the calculation for relative risk reduction?

Answer 5

Probability of outcome in an exposed group
= incidence in exposed/incidence in control
= (a/a+b) / (c/c+d)
-a = exposed with outcome
-b = exposed without outcome
-c = non-exposed with outcome
-d = non-exposed without outcome
-relative risk reduction = 1 - relative risk

***shortcut = a/c (risk of outcome in exposed/risk of outcome in unexposed)