STAT 100 Chapter 14: Chapter 14 STATS.docx

• School: Simon Fraser University
• Department: Statistics
• Course: STAT 100
• Professor: Derek Bingham

Document Summary

The most common way to display the relation between two quantitative variables is a scatterplot. Always plot the explanatory variable if there is one, on the horizontal axis of a scatterplot. If there is no explanatory response distinction, either variable can go on the horizontal axis. Look for the overall pattern and for striking deviations from that pattern. You can describe the overall pattern of a scatterplot by the direction, form, and strength of the relationship. An important kind of deviation is an outlier, an individual value that falls outside the overall pattern of the relationship. Two variables are positively associated when above-average values of one tend to accompany above-average values of the other and below-average values also tend to occur together. The scatterplot slopes upward as we move from left to right. Two variables are negatively associated when above-average values of one tend to accompany below-average values of the other, and vice versa.