Midterm Exam

Question 1

cumulative incidence per 1,000

Answer 1

(# of new cases)/(# of total persons at risk of developing the disease0 x 1,000

Question 2

incidence rate per 1,000

Answer 2

(# of new cases)/(total person-years) x 1,000

Question 3

prevalence per 1,000

Answer 3

(# of existing cases)/(total population) x 1,000

Question 4

point prevalence

Answer 4

cases at a singular point in time (ex: do you have asthma right now?)

Question 5

period prevalence

Answer 5

cases within a period of time (ex: have you had asthma in the past x years?)

Question 6

relative risk

Answer 6

(cumulative incidence in exposed) / (cumulative incidence in unexposed) OR (incidence rate in exposed)/(incidence rate in unexposed)

Question 7

cross-sectional studies are calculations of (prevalence/incidence)

Answer 7

prevalence

Question 8

cohort studies are calculations of (prevalence/incidence)

Answer 8

incidence

Question 9

as incidence increases, prevalence ____________

Answer 9

increases

Question 10

as deaths/cures from a disease in a population increases, prevalence _______

Answer 10

decreases

Question 11

prevalence of disease formula

Answer 11

a/(a+b)

Question 12

prevalence of exposure formula

Answer 12

a/(a+c)

Question 13

odds ratio formula

Answer 13

ad/bc

Question 14

in what type of study is an odds ratio utilized?

Answer 14

case-control study

Question 15

matched pairs odds ratios utilize (concordant pairs/discordant pairs)

Answer 15

discordant pairs

Question 16

3 assumptions of when an odds ratio is a good approximation of risk

Answer 16

1. a disease is rare
2. controls are representative of total population
3. cases are representative of all cases

Question 17

matched pairs odds ratio formula

Answer 17

b/c

Question 18

group matching can account for _______ variables

Answer 18

confounding

Question 19

formula for prevalence

Answer 19

prevalence = (incidence) x (duration of disease)

Question 20

formula for prevalence may only apply with the assumption that:

Answer 20

the population is in a steady state where (migration in = migration out)

Question 21

incidence in exposed

Answer 21

a/(a+b)

Question 22

incidence in non-exposed

Answer 22

c/(c+d)