Pop health 101

Question 1

equation for prevalence

Answer 1

number of cases in exposed / number of total people exposed

Question 2

equation for confidence interval

Answer 2

number of new cases/ initial population

Question 3

equation for incidence density

Answer 3

number of new cases/ time at risk

Question 4

equation for absolute risk

Answer 4

number of new cases/ study population

Question 5

relative risk

Answer 5

confidence interval of exposed / confidence interval of unexposed

Question 6

attributable risk

Answer 6

CI of exposed - CI of unexposed

Question 7

attributable risk percentage

Answer 7

(relative risk - 1)/ relative risk

Question 8

equation for odds ratio?

Answer 8

ad/bc where the columns are case and control (left to right) and the rows are exposed and unexposed (top to bottom)

Question 9

equation for sensitivity?

Answer 9

a/ (a+c)

Question 10

equation for specificity?

Answer 10

d/ (d+b)

Question 11

equation for positive predictive value?

Answer 11

a / (a+b)

Question 12

equation for negative predictive value?

Answer 12

d / (c+d)

Question 13

equation for LR+?

Answer 13

sensitivity / (1 - specificity)

Question 14

equation for LR-?

Answer 14

(1 - sensitivity)/ specificity

Question 15

equation for pre-test odds?

Answer 15

prevalence / (1- prevalence)

Question 16

equation for post-test odds?

Answer 16

pre-test odds x likelihood ratio

Question 17

equation for post-test probability?

Answer 17

post-test odds / (1 + post-test odds)

Question 18

equation for pre-test probability?

Answer 18

= prevalence

Question 19

equation for post-test probability?

Answer 19

= positive predictive value