AP PSYCHOLOGY

Detailed explanation-1: -Random assignment enhances the internal validity of the study, because it ensures that there are no systematic differences between the participants in each group. This helps you conclude that the outcomes can be attributed to the independent variable.

Detailed explanation-2: -Replication is vital to psychology because studying human behavior is messy. There are numerous extraneous variables that can result in bias if researchers are not vigilant. Replication helps verify that the presence of a behavior at one point in time is not due to chance.

Detailed explanation-3: -An operational definition is a description of how we will measure our variables, and it is important in allowing others understand exactly how and what a researcher measures in a particular experiment.

Detailed explanation-4: -Longitudinal study So, once again, researchers do not interfere with their subjects. However, in a longitudinal study, researchers conduct several observations of the same subjects over a period of time, sometimes lasting many years.