Research Principles

Question 1

What types of studies are subject to recall bias? (2)

Answer 1

Cross-sectional and case control

Question 2

what type of study samples subjects at one point in time for presence or absence of exposure and disease?

Answer 2

Cross sectional

Question 3

what parametric test compares means between two groups?

Answer 3

student t test

Question 4

what type of error occurs when the null hypothesis is falsely rejected?

Answer 4

alpha error (type 1 error)

Question 5

define relative risk (risk ratio)

Answer 5

risk of disease/death among people who are exposed divided by risk of disease/death among people who are not exposed

Question 6

define prevalence

Answer 6

a measure of disease present at one point in time

Question 7

Formula for sensitivity

Answer 7

TP / (TP+FN)

Question 8

X is assumed to cause Y, when in truth Z is common also and causes X and Y. What is Z?

Answer 8

confounding variable

Question 9

define beneficence

Answer 9

maximizing the benefits for the research project while minimizing the risks to the subjects

Question 10

when is it appropriate to use risk ratio/relative risk?

Answer 10

with a cohort study. cannot use with case-control bc researcher controls how many cases and controls (i.e. the risk ratio)

Question 11

when can you use an odds ratio?

Answer 11

with case control study or a cohort study

Question 12

Prevalence affects which of the following?
- sensitivity
-specificity
- PPV
- NPV

Answer 12

NPV and PPV

Question 13

Formula for specificity

Answer 13

TN / (TN + FP)

Question 14

define power

Answer 14

probability of avoiding type II error/ ability of a statistical test to detect a true difference in the sample of data

Question 15

define incidence

Answer 15

measure of individuals who develop a disease during a specified time period

Question 16

for acute conditions, which is generally greater: incidence or prevalence?

Answer 16

incidence

Question 17

name parametric and nonparametric tests that compare means between two groups

Answer 17

Parametric - student t test
Non parametric - Wilcoxon rank-sum test

Question 18

name parametric and nonparametric tests that compare means between three ore more groups

Answer 18

parametric - ANOVA
non parametric - Kruskal Wallis test

Question 19

name parametric and nonparametric tests that compare two quantitative measurements from one source

Answer 19

Parametric - paired t test
non parametric - Wilcoxon signed-rank test

Question 20

name parametric and nonparametric tests that determine degree of association between two quantitative variables

Answer 20

parametric - Pearson coefficient of correlation
non parametric - Spearman rank-order correlation

Question 21

what is statistical power?

Answer 21

probability of avoiding type II error (beta error) or ability of a statistical test to detect a true difference in the sample data
- type II error = null hypothesis is falsely accepted

Question 22

what is odds ratio?

Answer 22

magnitude of association between an exposure and an outcome

Question 23

what is relative risk ratio?

Answer 23

ratio of incidence among exposed vs unexposed

Question 24

relative risk is used in what kind of study?

Answer 24

cohort studies
- cannot be used in case-control study bc researchers control the risk

Question 25

odds ratio is used in what kind of study?

Answer 25

case control study

Question 26

likelihood ratio formula

Answer 26

SN/1-SP
- 1-SP = prob of false positive

Question 27

formula for NNT (2)

Answer 27

NNT = 1/ARR
- 1/ (%placebo - %tx)

Question 28

formula for ARR

Answer 28

ARR = EER - CER
(diff in event rate between experimental and control group)

Question 29

formula for RR

Answer 29

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

Question 30

formula for OR (with a,b,c,d)

Answer 30

(a x d) / (b x c)

Question 31

What outlines the ethical principles and guidelines for human subject research?

Answer 31

The Belmont Report