Biostats

Question 1

true positive/ (true positive + false negative)

Answer 1

Sensitivity

Question 2

probability that a patient with a disease will have (+) test result

Answer 2

Sensitivity (sensitive test rules out)

Question 3

true negative/ (true negative + false positive)

Answer 3

Specificity

Question 4

probability that a patient w/out a disease will have a (-) test result

Answer 4

Specificity (specific test rules in/ confirms)

Question 5

true positive / (true positive + false positive)

Answer 5

PPV (positive predictive value) = probability of disease

Question 6

A/(A+B) - C/(C+D) =

Answer 6

Attributable risk (disease in exposed/all exposed - disease unexposed/all unexposed)

Question 7

new cases/ pop at risk

Answer 7

incidence

Question 8

existing cases/ pop at risk

Answer 8

prevalence

Question 9

study that compares group with a disease to group without disease

Answer 9

case control

Question 10

compares group with a given risk/exposure to a group without that risk/exposure

Answer 10

cohort

Question 11

(A/(A+B))/(C/(C+D))

Answer 11

Relative Risk (risk of + in exposed/all exposed / risk of + in unexposed/all unexposed)

Question 12

(disease in placebo/all placebo) - (disease in tx/ all tx)

Answer 12

Absolute Risk Reduction

Question 13

1/Absolute Risk Reduction

Answer 13

Number Needed to Treat

Question 14

bias in which early detection can be confused with increased survival

Answer 14

lead time bias

Question 15

bias in which subjects in different arms of a study are systematically treated differently

Answer 15

procedure bias

Question 16

95% of data is within how many standard deviations?

Answer 16

2

Question 17

Odds ratio

Answer 17

(AD)/(BC)