Epidemiology Exam 2

Question 1

The two ways to represent data in a study are:

Answer 1

Quantitative and Qualitative

Question 2

A quantitative approach to represent data is divided into two study designs. Describe them.

Answer 2

Interventional (researcher-forced allocation to study groups)

Observational (no researcher-forced allocation into groups).

Question 3

What types of studies would be considered interventional? Observational?

Answer 3

Interventional: Clinical trials, clinical studies.

Observational: Cross-sectional, case-control, cohort.

Question 4

What types of trials show the strongest research evidence, according to the research evidence pyramid? Weakest?

Answer 4

Strongest to weakest (top 5): Meta-analyses/systematic reviews, interventional/pragmatic trials, cohort, case-control, cross-sectional.

Weakest strength of evidence: animal and in-vitro research.

Question 5

____ studies are the only ones that can prove causation, but they are costly and can have difficult ethical considerations.

Answer 5

Interventional

Question 6

Is the “study population” a sample or a population?

A ____ is a subset of a population.

Answer 6

The “study population” is a sample and the final group of individuals selected for a study.

Sample.

Question 7

Studies involving ____ patients are the classic example of studies that are too restrictive. They usually have many other co-morbidities.

Answer 7

Mental health.

Question 8

The various selection criteria utilized in the different studies impacts ____, which impacts the study’s ____.

Answer 8

Generalizability.

External Validity.

Question 9

Researchers either reject or don’t reject this perspective, based on the results generated.

Answer 9

Null hypothesis (Ho)

Question 10

Describe the three different statistical perspectives a researcher can approach for a study and state the null hypothesis for each approach.

Answer 10

Superiority: “X will not be superior to Y (Y is usually placebo).”

Noninferiority: “X is worse than Y.”

Equivalency: “X is not equal to Y.”

Question 11

What is a Type I error and a Type II error.

Answer 11

I: false positive
II: false negative

Question 12

What is a probability sample?

Answer 12

A probability sample is the most common type of sampling scheme. Basically, it works off the premise that every element in the population has a known (non-zero) probability of being included in a sample.

Question 13

What are the six types of probability, random sampling schemes?

Answer 13

1. Simple random sampling.
2. Systematic.
3. Stratified simple.
4. Stratified disproportionate.
5. Multi-stage.
6. Cluster multi-stage.

Question 14

Describe the 6 different random sampling schemes

Answer 14

Simple: assign random numbers then select randomly selected numbers or sequentially list numbers and take the desired sample size.

Systematic: assign random numbers, randomly sort number, set up a type of system by, for example, taking every Nth number to get desired sample size.

Stratified Simple: Stratify into groups based on your characteristic, then use simple random sampling.

Stratified Disproportionate: Disproportionately utilizes stratified simple when baseline population is not at the desired proportional percentages to the referent population. (Can utilizing ‘weighting’ or ‘over-sampling)

Multi-stage: simple random sampling at multiple-stages towards patient selection.

Cluster multi-stage: Just like multi-stage, but ALL ‘elements’ at any stage are clustered together.