2. What is a scatter plot?
Study Time Grades
• Collection of ordered
pairs 2
4
2
6
• Shows relationship 5
6
7
8
between 2 different 7 9.5
sets of data
Scatter Plot
• Shows what kind of 10
7, 9.5
relationship exists 8 6, 8
Test Scores
5, 7
6 4, 6
between the data 4
2 2, 2
0
0 1 2 3 4 5 6 7 8
Study Time
3. 3 Types of
Correlation/Association
• Positive - as one value goes up, the other goes
up
Positive
10
8
Test Scores
6
4
2
0
0 1 2 3 4 5 6 7 8
Study Time
4. 3 Types of
Correlation/Association
• Negative - as one value goes up, the other
goes down
Negative
14
Number of Clothes Items
12
10
8
6
4
2
0
0 20 40 60 80 100
Temperature
5. 3 Types of
Correlation/Association
• No correlation - as one value goes up, the other
neither goes up or down
6. FITTING A LINE TO DATA
8
There are several ways to line
Usually, there is no single 6
find the line through all for a
that passes of best fit the
givenpoints, data points. In
data set of so you try to find 4
this line that you will use a
the lesson, best fits the data.
graphicalbest-fitting line.
This is called the best-fitting
approach. 2
line.
–8 –6 –4 –2 0 2 4 6
–2
–4
–6
–8
7. Approximating a Line of Best Fit
250
DISCUS THROWS 240
230
The winning Olympic
discus throws from 220
1908 to 1996 are 210
plotted in 200
Distance (ft)
the graph. Approximate 190
the best-fitting line for 180
these throws.
Write an equation of 170
your line. 160
150
140
130
120
110
100
0 8 16 24 32 40 48 56 64 72 80 88 96 104
Years since 1900
8. DETERMINING THE CORRELATION/ASSOCIATION OF X AND Y
In this scatter plot, x and y
have a positive
association, which means
that the points can be
approximated by a line with
a positive slope.
Examples:
Age and Height
Temperature and ice cream
sales
Time elapsed and miles
travelled
9. DETERMINING THE CORRELATION/ASSOCIATION OF X AND Y
In this scatter plot, x and y
have a negative
association, which
means that the points can
be approximated by a line
with a negative slope.
Examples:
Car age and car value
Temperature and hot
chocolate sales
Miles travelled and
distance to destination
10. DETERMINING THE CORRELATION/ASSOCIATION OF X AND Y
In this scatter plot, x and y
have relatively no
association, which means
that the points cannot be
approximated by
a line.
Example:
Age and eye color
Number of pets and
touchdowns scored
