Biostats/Epi. Flashcards Preview

USMLE Step 1 > Biostats/Epi. > Flashcards

Flashcards in Biostats/Epi. Deck (27):
1

Cross-sectional study measures....

Disease prevalence

2

Case-control study measures...

Odds ratio (OR)

3

Cohort study measures....

Relative risk (RR)

4

Prevalence of diseases with short duration =

roughly the incidence rate

5

OR =

(A/C) / (B/D)

6

RR =

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

7

AR =

a/a+b - c/c+d

8

RRR =

1 - RR

9

ARR -

c/c+d - a/a+b

10

NNT =

1/ARR

11

NNH =

1/AR

12

Attributable risk % in the exposed =

100 x (RR-1)/RR

13

Increased precision...

Increased statistical power

14

berkson bias

study pop selected from hospital is less healthy than general pop

15

Pygmalion effect

Researchers belief in efficacy of Tx changes the outcome

16

Hawthorne effect

subjects change behavior when they know they are being observed (observer effect)

17

SEM (standard error of the mean) =

SD/square root of n (SEM decreases w/ increased sample size

18

Increased power by:

increasing sample size, expected effect size, precision of measurement

19

For the 95% CI, Z = For the 99% CI, Z =

1.96 2.58

20

CI =

mean +/- Z x SEM

21

Sensitivity =

1 - false negative rate

22

Specificity =

1 - false positive rate

23

Errrors

A image thumb
24

Coeffecient of determination

R2

25

Medicare

Patients above 64

Under 65 with certain disabilites

Those with end-stage renal disease

26

Medicaid

Joint federal and state program for people with very low income

27

Medicare parts

A - hospital insurAnce

B - Basic medical Bils

C - (Parts A+B) delivered by approved private Companies

D - Prescription Drugs