1. Statistics
E4 Scatter Plots

2. E4 Scatter Plots Positive Correlation – _________ pattern upward
Negative Correlation – _________ pattern
downward
No Correlation – _____ pattern no

3. Example 1 negative positive none What kind of pattern is this?
upward, downwards, or no pattern
no pattern
upwards
downwards

4. Line of Best Fit
__________ line that is “closest” to a set of data points
STRAIGHT
You do NOT connect all the points!
Just draw a STRAIGHT line through most of the points

5. Line of Best Fit About 650 million
Example 2: The scatter plot shows the number of CD’s (in millions) that were sold from 1999 to If the trend continues, about how many CD’s were sold in 2006?
Draw a straight line that represents the pattern of the data
About 650
million
2006

6. Line of Best Fit
Example 3: The number of hours spent on math homework each week and the final exam grades for twelve students in Mr. Dylan’s algebra class are plotted on the graph
A. What type of correlation is it?
(1) positive
negative
(3) no correlation
(4) cannot be determined
Draw a straight line that represents the pattern of the data

7. Line of Best Fit
B: Based on a line of best fit, which exam grade is the best prediction for a student who spends about 4 hours on math homework each week?
(1) 62 72
(3) 82
(4) 92

8. In Closing
Explain why a line of best fit does not connect the dots like a line graph

9. Practice Problems
Now try the practice problems on your own