Experimental Designs and Methods

These flashcards cover key concepts related to experimental designs and methods, including types of variables, study designs, biases, validity, and reliability, essential for understanding research design for the MCAT.

What percentage of MCAT questions in the science section are based on passages related to scientific experiments?

75%

Define 'independent variable.'

The variable that is manipulated in an experiment to observe its effect on the dependent variable.

Define 'dependent variable.'

The variable that is measured in an experiment and is expected to change as a result of the independent variable.

What is a confounding variable?

A third variable that affects both the independent and dependent variable and may obscure the true relationship between them.

What kind of variable is familial hypercholesterolemia in relation to coffee drinking and cardiovascular disease?

It is not a confounding variable because it does not have a relationship with coffee drinking.

What does a mediating variable do?

Provides a causal link between two variables in an observed relationship.

How do moderating variables affect relationships between other variables?

They modulate the intensity or strength of the relationship.

What is operationalization in research?

The process of defining and measuring variables in a way that can be practically assessed.

What are the two main types of study designs?

Experimental studies and observational studies.

What is a randomized controlled trial (RCT)?

An experimental study design where participants are randomly assigned to either a treatment group or a control group.

What is the purpose of positive controls in experimental studies?

To confirm the adequacy and competency of the experimental procedures.

What are negative controls used for?

To demonstrate whether an intervention has an actual effect.

What does blinding in an experiment help to minimize?

Bias in the outcome measurements by keeping participants and/or researchers unaware of group assignments.

Explain the difference between cross-sectional studies and longitudinal studies.

Cross-sectional studies provide a snapshot of a population at a single point in time, while longitudinal studies gather data over multiple time points.

What is a case-control study?

A study design that compares individuals with an outcome of interest to those without, to identify differences that could reveal causes.

What are self-reporting biases?

Biases that arise when participants provide answers based on their personal judgments rather than objective measures.

What is social desirability bias?

The tendency of participants to respond in a way that is socially acceptable rather than truthful.

What is representativeness in survey research?

The idea that a sample should accurately reflect the demographics of the population from which it is drawn.

Define internal validity.

The extent to which we can draw causal conclusions from a study's data.

Define external validity.

The extent to which we can generalize study findings to real-world situations.

How can construct validity be assessed?

By evaluating if a test measures what it is intended to measure.

What does reliability in research refer to?

The consistency of measurements across different trials or observers.

Differentiate between qualitative and quantitative research methods.

Qualitative methods produce non-numerical data, while quantitative methods yield numerical data.

What is the main goal of much biomedical research?

To establish cause-and-effect relationships.