Final answer:
Random assignment is a method used in experiments to equally distribute participants across different groups to eliminate bias and control for lurking variables, whereas random selection is the process of choosing a representative sample from a larger population to avoid selection effects.
Step-by-step explanation:
Random assignment differs from random selection in that random assignment is a procedure used in experimental design to allocate participants to different groups with an equal chance. This process helps to ensure that there are no systematic differences between groups in terms of demographics or other variables, which could influence the outcome of the experiment. On the other hand, random selection or random sampling refers to the method by which a representative sample is chosen from a larger population for the purposes of research. The primary goal of random sampling is to obtain a sample that accurately reflects the characteristics of the larger population.
Using random assignment, researchers can control for lurking variables by ensuring that each participant has an equal chance of being placed in any given treatment group, whether that's an experimental group or a control group. In contrast, random selection is about how to draw a sample from a population in a way that gives every individual an equal opportunity to be chosen, which helps to ensure that the sample is representative of the wider population, thereby avoiding a selection effect. Both processes are critical to ensuring the integrity of research findings, but they serve different purposes in the experimental and sampling processes.