http://www.ck12.org Chapter 9. Regression and Correlation
- A negative correlation– When the points on a scatterplot graph produce a upper-left-to-lower-right pattern
(see below), we say that there is anegative correlationbetween the two variables. This pattern means that
when the score of one observation is high, we expect the score of the other observation to be low and vice
versa. - A perfect correlation– If there is a perfect correlation between the two variables, all of the points in the
scatterplot will lie on a straight line (see below). - Zero correlation– A scatterplot in which the points do not have a linear trend (either positive or negative) is
called a zero or a near-zero correlation (see below).