  ### Home > CCAA8 > Chapter 7 Unit 8 > Lesson CCA: 7.1.2 > Problem7-29

7-29.

Scientists hypothesized that dietary fiber would impact the blood cholesterol level of college students. They collected data and found $r=-0.45$ with a scattered residual plot. Interpret the scientists’ findings in context.

The Math Notes box in your textbook states: The correlation coefficient, r, is a measure of how much or how little data is scattered around the LSRL; it is a measure of the strength of a linear association. The correlation coefficient can take on values between $–1$ and $1$. If $r = 1$ or $r = -1$, the association is perfectly linear. There is no scatter about the LSRL at all. A positive correlation coefficient means the trend is increasing (slope is positive), while a negative correlation means the opposite. A correlation coefficient of zero means the slope of the LSRL is horizontal and there is no linear association whatsoever between the variables.

What does a negative $r$ value mean? How does that definition apply to this situation?