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Flashcards in Biostatistics-Observational Studies Deck (7)
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1
Q

What measure of association is commonly used in a case control study?

A

Usually an odds ratio. This is because case control studies tend to not get as good of values for incidence.

2
Q

What tests are used to determine statistical significance of means? Proportions?

A

Mean comparison = T-test, Analysis of Variance. Proportion comparison = Chi square, McNemar’s (paired data).

3
Q

Why are hospital studies not always the best place to do a study?

A

External validity is compromised because your population is not a good representation of the outside community. Internal validity is compromised because of recall bias (sick people recall events leading to their condition better)

4
Q

What type of study would minimize misclassification of people as controls?

A

Cohort. You don’t know whether their going to be a case or control at the beginning of the study.

5
Q

How is confounding addressed?

A

Matching (attempts to compare people in the same scenario to eliminate confounders), Stratification (separate your measures of association into sub-groups to expose and separate confounders) and Adjustment.

6
Q

What measure of association is used in a cohort study?

A

Risk ratio. This is because you get a good level of incidence.

7
Q

What are standard biases in cohort studies?

A

Exposed and unexposed groups are not equally susceptible for reasons unrelated to the exposure, group crossover between subjects, drop-out and tendency to measure exposed group more closely than unexposed.