Biostat

Question 1

number of groups: 1
type of data: parametric tests (data has normal distribution)

Answer 1

One-sample t-test

Question 2

number of groups: 1
type of data: non-parametric tests (data has skewed distribution)

Answer 2

sign test

Question 3

number of groups: 1
type of data: discrete/categorical

Answer 3

chi-square test

Question 4

number of groups: 1 (with before & after measures)
type of data: parametric tests (data has normal distribution)

Answer 4

dependent/paired t-test

Question 5

number of groups: 1 (with before & after measures)
type of data: non-parametric tests (data has skewed distribution)

Answer 5

Wilcoxon Signed-Rank test

Question 6

number of groups: 1 (with before & after measures)
type of data: discrete/categorical

Answer 6

Wilcoxon Signed-Rank test

Question 7

number of groups: 2 (treatment & control)
type of data: parametric tests (data has normal distribution)

Answer 7

Independent/Unpaired student t-test

Question 8

number of groups: 2 (treatment & control)
type of data: non-parametric tests (data has skewed distribution)

Answer 8

Mann-Whitney (Wilcoxon Rank-Sum) test

Question 9

number of groups: 2 (treatment & control)
type of data: discrete/categorical

Answer 9

Chi-square test or Fisher’s exact test
Mann-Whitney (Wilcoxon Rank-Sum) test may be preferred for ordinal data

Question 10

number of groups: >3
type of data: parametric tests (data has normal distribution)

Answer 10

ANOVA (or F-test)

Question 11

number of groups: >3
type of data: non-parametric tests (data has skewed distribution)

Answer 11

Kruskal-Wallis test

Question 12

number of groups: >3
type of data: discrete/categorical

Answer 12

Kruskal-Wallis test

Question 13

correlation

Answer 13

used to determine if one variable changes, or is related to another variable. correlation does not prove causal relationship

Question 14

Regression

Answer 14

describe a relationship between a dependent variable and one or more independent variables

1) linear regression for continuous data
2) logistic regression for categorical data
3) cox regression for categorical data in a survival analysis

Question 15

sensitivity

Answer 15

A/(A+C) x 100
look in notes

Question 16

Specificity

Answer 16

D/(A+D) x 100
look in notes

Question 17

Intention-to-treat

Answer 17

all patients originally allocated for each treatment group

Question 18

per protocol

Answer 18

only pts who completed the study according to the protocol

Question 19

clinical trials can be analyzed two different ways

Answer 19

Intention-to-treat
per protocol

Question 20

two types of trial

Answer 20

equivalence- new tx is roughly the same as old tx
– these trails test for effect int wo directions for higher or lower effectiveness (two-way margin)

non-inferiority trails- new tx is no worse than the current standard based on the predefined non-inferiority (delta) margin. delta margin is minimal difference in effect between the two groups is considered clinically acceptable based on previous research

Question 21

forest-plots

Answer 21

generally in meta-analysis
provide CI for difference data or ratio data
– boxes: effect estimate from single study shown
– diamond: at bottom show pooled results form multiple studies
– horizontal lines: confidence intervals, longer lines less reliable
– vertical solid line: is no effect line. significant benefit shown if it falls left of line, right of line is significant harm. verticle line is set for zero for difference data or one for ratio data

Question 22

cohort study

Answer 22

compares outcomes of a group of pt exposed and not exposed to a tx
follows boths groups prospectively (in the future)

limitations: time-consuming, expensive, can be influenced by confoundets (other factors that affect outcomes…smoking, lipid levels, etc.)

Question 23

cross-sectional survey

Answer 23

estimates a relationship between variable and outcomes prevalence in one particles time in a defined population

Question 24

case report/ case series

Answer 24

singe patient case report or few patients case series… describes adverse reaction

Question 25

Randomized controlled trial (RCT)

Answer 25

radominzed…equal chances
- double-blind
- single-blind
- open label

Question 26

crossover RCT

Answer 26

group 1- tx a then b
group 2 tx b then a

Question 27

factorial design

Answer 27

randomized to more than two groups to test number of experimental conditions

Question 28

meta-analysis

Answer 28

combines results form multiple studies in order to develop a conclusion that has greater statistical power

Question 29

systematic review

Answer 29

summary of clinical literature, on specific topic or question

Question 30

incremental cost ratio

Answer 30

(c2-c1)/(E2-E1)

Question 31

cost-minimization analysis

Answer 31

CMA- when two or more interventions have demonstrated equivalence in outcomes and the cost of each intervention are being compared.

demonstrated or assumed to be equivalent in comparative groups- outcome unit

Question 32

cost-benefit analysis

Answer 32

comparing benefit and cost of an intervention in terms of monetary unit

dollars- outcome unit

Question 33

cost-effective analysis

Answer 33

clinical effects, two or more interventions to the respective costs

natural units (life-years gained, mmHg blood pressure, % at treatment goal)- outcome unit

Question 34

types of medical studies from more reliable to less

Answer 34

systematic reviews and meta-analysis
randomized controlled trials
cohort studies
case-control studies
case series and case reports
expert opinion

Question 34

cost-utility analys

Answer 34

quality-of-life component of morbidity assessments, using common health indices, QALYs, (quality-adjusted life years), DALYs (disability-adjusted life years)

QALY or other utilities- outcome unit

Question 34

case-control study

Answer 34

comparies pt w/ disease (case) to those w/out (control). retrospectively

limitations: cause and effect cannont be reliably determined