Which of the following best defines the term "correlation"?

The term "correlation" is best defined as a measure of how two variables change together. This concept highlights the relationship between the variables, indicating whether they tend to increase or decrease in relation to one another. Correlation does not imply causation; it simply reflects the extent to which two variables are associated or move together. For instance, if one variable increases while the other tends to increase as well, there is a positive correlation. Conversely, if one variable increases while the other decreases, there is a negative correlation.

The other definitions provided do not accurately describe correlation. A sequence of events in an experiment refers to the procedural steps taken during a scientific study. A relationship where one variable causes change in another describes causation rather than correlation, emphasizing a direct cause-and-effect connection rather than mere association. A fixed outcome in an experimental study refers to a predetermined result or conclusion, which does not pertain to the concept of correlation at all. Thus, option C encapsulates the true meaning and application of correlation in the context of statistics and data analysis.