Biostats

Question 1

Bias when people change their behavior when they know they’re being observed =

Answer 1

Hawthorne bias

Question 2

Sick patients remember more? Bias?

Answer 2

Recall bias

Question 3

Blinding of subjects helps to avoid which types of bias?

Answer 3

Recall and Hawthorne

Question 4

Randomization prevents which bias?

Answer 4

Selection bias (happens when groups are different at baseline)

Question 5

Use randomization and ___ to prevent selection bias

Answer 5

matching

Question 6

Blinding of researchers prevents which bias?

Answer 6

Observer bias

Question 7

Exposure and outcome are related but there might be a third factor affecting the outcome! What is this?

Answer 7

Confounding!
example: ice cream associated with drowning; third factor is SUMMER (Summer negates the causal relationship between ice cream and drowning)

Question 8

If the third factor IS NOT related to the exposure but the third factor enhances the effect of the tested exposure

Answer 8

Effect Modification
ex: OCPs increasing risk of DVT, with third factor being smoking (smoking enhances the relationship between OCPs and DVTs)

Question 9

An observational, retrospective study that compares the odds of being exposed between patients with disease and patients without the disease =

Answer 9

Case-control study

Question 10

Odds Ratio is a measure of disease association in what study type?

Answer 10

Case-control study

Question 11

Example of study: patients with cirrhosis are more likely to have been exposed to heavy alcohol use

Answer 11

Case-control study

Question 12

Observational study, either retrospective or prospective, that compares a given group with a risk factor to a group without the risk factor to see if there’s increased likelihood of the disease

Answer 12

Cohort Study

Question 13

Relative risk is a measure of disease association for what study?

Answer 13

Cohort study

Question 14

Study that asks how much more likely are you to get cirrhosis if you drink alcohol?

Answer 14

Cohort study

Question 15

A ___ study measures disease prevalence and determines association but not causality

Answer 15

Cross-sectional

Question 16

A study that randomizes patients into different interventions with 2 or more variables being studied in each intervention

Answer 16

Factorial design study

Question 17

Participants alternate receiving intervention and placebo

Answer 17

Crossover study

Question 18

What kind of bias is represented when patients with severe disease are less likely to be studied because they die?

Answer 18

Late-look bias

Question 19

Early detection looks like increase in survival, what bias?

Answer 19

Lead-time bias

Question 20

The pygmalion effect is described as

Answer 20

a self-fulfilling prophecy

Question 21

Effect modification is NOT a type of

Answer 21

bias

Question 22

Which phase of study involves a small number of healthy subjects and determines safe dose range and side effects?

Answer 22

Phase I

Question 23

Which phase involves a small number of diseased patients and refines dosage and safety profile?

Answer 23

Phase II

Question 24

Which phase of a study involves a large number of diseased patients, confirms effectiveness, and compares to standard of care?

Answer 24

Phase III

Question 25

Which phase involves post-marketing surveillance and detects rare or long-term adverse effects?

Answer 25

Phase IV