WT - Biostats

Question 1

Studies with controls

Answer 1

clinical trial
case control
prospective/retrospective cohort

Question 2

Studies w/ patients as their own controls

Answer 2

crossover study

Question 3

Studies without control

Answer 3

cross-sectional

case series

Question 4

study typically determining odds ratio

Answer 4

case control

-compares group with disease to a group w/o disease

Question 5

study typically determining relative risk

Answer 5

cohort

-compares group with a given exposure to a group w/o such exposure

Question 6

study typically determining disease prevalence

Answer 6

cross sectional

Question 7

study comparing effect of a series of 2 or more tx on a participant

Answer 7

crossover study

Question 8

study examining natural hx

Answer 8

case series

Question 9

cohort studies are organized by

Answer 9

• selecting group who do NOT have disease of interest
• det their exposure status
• following to assess for development of disease

Question 10

Odds ratio

Answer 10

ad/bc

measure of strength of association between exposure and outcome

Question 11

Relative risk

Answer 11

(a/(a+b))/(c/(c+d))

probability of outcome occurring in exposed group vs unexposed group

Question 12

relative risk reduction

Answer 12

1-RR

1-(a/(a+b))/(c/(c+d))

Question 13

attributable risk

Answer 13

(a/a+b)-(c/c+d)

Question 14

absolute risk reduction

Answer 14

(c/c+d)-(a/a+b)

Question 15

NNT

Answer 15

1/ARR

lower #, better tx

Question 16

NNH

Answer 16

1/AR

higher #, safer exposure

Question 17

odds ratio/relative risk

Answer 17

measure strength of assoc btwn 2 categorical variables

exp

1. categorical risk (smoke)
2. categorical outcome (MI)

Question 18

ANOVA

Answer 18

compares mean of quantitative variables of _/> 3 indep groups

exp

• serum ferritin levels in 3 dif age groups
• FEV1 in light/med/heavy smokers

Question 19

results of _________ will be equiv when comparing dif btwn means of 2 groups

(2 tests)

Answer 19

t-test and ANOVA

Question 20

regression analysis

Answer 20

describes effect of 1 or more independent variables (exposures, risk fx) which may be QUANT or QUAL, on one QUANT dependent variable (binary outcome)

exp
-egg and meat consumption affecting [serum ferritin]

Question 21

chi square

Answer 21

compares 2 categorical variables (large sample size)

exp
FEV1 and smoking status

Question 22

fisher exact test

Answer 22

compares 2 categorical variables (small sample size)

exp
FEV1 and smoking status

Question 23

2 sample T-test

Answer 23

compares the dif between the numerical means of 2 groups

Question 24

normal distribution

Answer 24

16 - 68 - 16

2. 5 - 95 - 2.5
3. 15 - 99.7 - 0.15

Question 25

odds/risk ratio including __ –> exposure/risk is NOT significant outcome

Answer 25

1

Question 26

if CI includes ___ or if ____, then no statistical diff between groups

Answer 26

zero

or if CI overlap between 2 groups