Copy in Agenda and TOC: #10 Scatter
Plots – Linear/Nonlinear, Clusters,
Outliers
• Opening:
• Explain whether the bivariate data has a positive, negative, or no
correlation.
1. Advertisement of a movie vs. movie ticket sales
2 Test scores vs. popularity
3. The amount of people on a free WIFI network vs. speed of Internet
Review
• Positive correlation
• As x increases y increases
• Negative correlation
• As x increases y decreases
• No correlation
• No obvious pattern
Linear/Nonlinear Association
• Linear equations
• y = mx+b
• Form a line
Linear/Nonlinear Association
• Linear association: When the data points appear to lie in
the shape of a line.
Positive linear association
Negative linear association
Linear/Nonlinear Association
• Nonlinear association: When the data points appear to
line in the shape of a curve.
Special Case – No Correlation
• *Since scatter plots with no correlation are neither linear
nor nonlinear we say that they have no correlation and no
association.*
No correlation/no association
Clusters and Outliers
• Cluster: A collection of points that are close together.
• Outlier: A value that “lies outside” most of the values of
data.
Closing