Key Concepts in Research and Statistics

What is convenience sampling?

• A method where samples are selected randomly from the entire population.

• A non-random sampling method where units are selected for inclusion in the sample because they are the easiest to access.

• A technique that ensures every member of the population has an equal chance of being selected.

• A sampling method that requires extensive resources and time to gather data.

What is a quasi-experiment?

• A research study that manipulates an independent variable to find a cause-and-effect relationship but lacks random assignment.

• A type of experiment that uses random assignment to control variables.

• A study that observes subjects in their natural environment without manipulation.

• An observational study that compares two or more groups without intervention.

What is a control group?

• The subset of subjects in an experiment that does not receive the active treatment or independent variable being tested.

• The group of subjects that receives the full treatment in an experiment.

• A group that is used to compare results against the experimental group.

• The group of subjects that is randomly selected for the experiment.

What is a confound?

• A factor that complicates potential causal relationships as they relate to both X and Y.

• A variable that is manipulated in an experiment.

• A statistical method used to analyze data.

• A type of bias that affects the validity of research.

What is external validity?

• How well a study generalizes to other scenarios.

• The accuracy of the measurements used in a study.

• The degree to which a study can be replicated.

• The extent to which the results of a study are statistically significant.

What is variance?

• The average of squared deviations from the mean.

• The sum of all data points divided by the number of points.

• The difference between the highest and lowest values in a dataset.

• The square root of the mean of squared deviations.

What is internal validity?

• How well a study captures the causal claim it seeks to measure.

• The extent to which results can be generalized to a larger population.

• The degree to which a study measures what it claims to measure.

• The reliability of the data collected in a study.

What is random assignment?

• Starting with a sample and then dividing it into two or more groups.

• Assigning participants to groups based on their preferences.

• Selecting a random sample from a population without grouping.

• Dividing a sample into equal parts based on age or gender.

What is a hypothesis?

• A testable and specific prediction about the relationship between one or more independent variables and the dependent variable.

• A general statement that cannot be tested.

• An observation made during an experiment.

• A conclusion drawn from data analysis.

What is the Fundamental Problem of Causal Inference?

• The idea that we can never observe the same unit in both the treatment and control condition at the same time; we can only observe one potential outcome per unit.

• The assumption that all units are identical and can be treated the same way in experiments.

• The belief that causal relationships can be established without any experimental data.

• The notion that correlation implies causation in statistical analysis.