The key to getting a representative sample is: a. Random assignment b. Random selection c. Replication d. Correlation

The key to getting a representative sample is b. Random selection.

Here's why:

A representative sample is a subset of a statistical population that accurately reflects the members of the entire population. To achieve this, you need to ensure that every individual in the population has an equal chance of being selected. This is done through random selection.

Random assignment, on the other hand, is a method used in experiments to reduce bias and ensure that the groups being compared are similar in all respects except for the variable being tested.

Replication is the repetition of an experimental condition so that the variability associated with the phenomenon can be estimated.

Correlation is a statistical measure that describes the size and direction of a relationship between two or more variables.

So, while all of these are important concepts in research, the key to getting a representative sample is random selection.