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Flashcards in Biostats Deck (10):
1

measures PREVALENCE of disease
Collects data from a group of people to assess the frequency of disease & related risk factors at a particular point in time

Cross-sectional study
(observational)

2

Compares a group of people with disease to a group without a disease
Looks for prior exposure or risk factor
Measure: ODDS RATIO

Case-control study
(observational & retrospective)

3

Compares a group with a given risk factor or exposure to a group without
Looks to see if exposure increases likelihood of disease
Measure: RELATIVE RISK

Cohort study
(observational & prospective or retrospective)

4

nonrandom assignment to participate in a study group

selection bias
Includes sampling bias:
1. Berkson bias -> only looking at inpatients
2. Loss to follow-up
3. healthy worker and volunteer bias

5

Awareness of the disorder alters the recall by subjects; common in retrospective studies

Recall bias

6

Information is gathered in a way that distorts it

Measurement bias
Hawthorne effect: groups who know they are being studied behave differently -> use placebo control groups and blinding to fix

7

Subjects in different groups are not treated the same

Procedure bias

8

when a factor is related to exposure & outcome but not the causal pathway, it distorts or confuses effect of exposure on outcome

Confounding bias

9

early detection is confused with increased survival

Lead-time bias

10

measures of central tendency

Mean, median, mode
In the normal distribution, Mean = Median = Mode