Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

FA > Epi/Biostats > Flashcards

Epi/Biostats Flashcards

1
Q

Cross-sectional Study

A

observational
assesses frequency of disease at a particular point in time
measures disease prevalence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Case-control Study

A

observational
compares group with disease to a group without disease to look for exposure
measures odds ratio

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Cohort Study

A

observational
compares group with exposure that without
measures relative risk
prospective OR historical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Twin Concordance Study

A

compares frequency of disease in MZ or DZ twins

nature vs nurture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Adoption Study

A

compares siblings with bio vs adoptive parents

nature vs nurture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Phase I clinical trial

A

small # healthy volunteers

safety, tox, PK, PD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Phase II clinical trial

A

small # of pts with disease

efficacy, dosing, AE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Phase III clinical trial

A

Large # of pts, random assignment

compare to standard therapy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Phase IV clinical trial

A

post-marketing surveillance

AE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Sensitivity

A

True Positive Rate=TP/(TP+FN)
probability of a positive test when the disease is present
high = low FN rate
SN-N-OUT (highly SeNsitive test, when Negative, rules OUT disease)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Specificity

A

True Negative Rate=TN/(TN+FP)
probability of a negative test when the disease is absent
high=low FP rate
SP-P-IN (highly SPecific test, when Positive, rules IN disease)
confirm after + screening test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Positive predictive value

A

PPV=TP/(TP+FP)
probability that a person with a + test actually has the disease
varies directly with disease prevalence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Negative predictive value

A

NPV=TN/(TN+FN)
probability that a person with a - test actually does not have the disease
varies indirectly with disease prevalence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Incidence

A 
# of new cases/# at risk
during a specified time period
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Prevalence

A 
# of existing cases/total#
at a point in time
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Odds ratio

A

odds that the group with the disease was exposed to a RF divided by the odds that the group without the disease was exposed

17
Q

Relative Risk

A

Risk of developing disease in the exposed group divided by risk in the unexposed group
equals OR at low prevalence

18
Q

Attributable Risk

A

Difference in risk between exposed and unexposed groups

the proportion of disease occurrences that are attributable to the exposure

19
Q

Relative Risk Reduction

A

the proportion of risk reduction attributable to the intervention as compared to a control
RRR=1-RR

20
Q

Absolute Risk Reduction

A

difference in risk attributable to the intervention as compared to a control

21
Q

Number Needed to Treat

A 
NNT=1/ARR
# of patients who need to be treated for 1 pt to benefit
22
Q

Number Needed to Harm

A 
NNH=1/AR
# of patients who need to be exposed to a RF for 1 pt to be harmed
23
Q

Precision

A

consistency, reproducibility, reliability
absence of random variation (SD)
increases power

24
Q

Accuracy

A

trueness, validity

absence of systematic error or bias

25
Q

Selection Bias

A

error in recruiting and assigning subjects

may correct with randomization

26
Q

Recall Bias

A

awareness alters recall by subjects

common in retrospective studies

27
Q

Measurement Bias

A

distorted info gathering

correct with standardized testing

28
Q

Procedure Bias

A

subjects in different groups are not treated the same

can correct with blinding and placebo use

29
Q

Observer-expectancy bias

A

when the researcher believes the treatment is efficacious

use blinding and placebo

30
Q

Confounding bias

A

when a factor is related to both exposure and outcome but not in same causal path
can match or randomize

31
Q

Lead-time bias

A

early detection is confused with increased survival

32
Q

Normal distribution

A

68% between 1 SD either side of mean
95% between 2 SD
99.7% between 3 SD

33
Q

Type I error (alpha)

A

stating that there is a difference when none exists
incorrectly reject the null hypothesis
False-positive error
alpha level

34
Q

Type II error (beta)

A

the null hypothesis is not rejected when it is false
stating that there is not a difference when one exists
false-negative error

35
Q

Power

A

1-beta
probability of rejecting the null when it is false
increases with sample size, expected effect size, and precision

36
Q

Confidence Interval

A

range of values within which the true mean falls
CI=mean+/-Z(SEM)
95% CI for p=0.05

37
Q

t-test

A

difference between means of 2 groups

38
Q

ANOVA

A

differences between means of 3 or more groups

39
Q

Chi-square

A

differences between 2 or more proportions of CATEGORICAL outcomes

FA (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions