Glossary
Correlation measures how strongly two variables are related to each other.
Positive Correlation - as values on one variable increase, the values on the
other measure also increases.
Example - As height goes up, weight goes up.
Negative Correlation - as values of one variable increases, the value of the
other decreases.
Example - The older the car, the lower the price. The more you watch tv, the
lower your grades.)
Coefficient of Correlation - a measure of correlation that indicates the size
and direction of the relationship between two variables.
Example:
A correlation of .15 suggests a weak relationship and .75 suggests a very strong
relationship. A correlation of +.15 means it is a positive correlation and, -.75
indicates a negative correlation.
Key Concepts Explained
Although a correlation indictes the size and direction of the relationship between
variables, it does not indicate that one causes the other.
Example: The high positive correlation between storks nesting and the number
of human births in European villages does not mean that storks bring babies.
Activities
Links
wwwlink: A discussion of "spurious'
correlations.
wwwlink: Baseball
announcers make spurious correlations too.