Transcript Make Predictions from Scatter Plots

MAKE PREDICTIONS
FROM SCATTER PLOTS
MAKE PREDICTIONS
 Scatter Plots show a positive trend if y tends to increase as x
increases or if y tends to decrease as the x decreases.
 Scatter Plots show a negative trend if one value tends to
increase and the other tends to decrease.
 A scatter plot shows no trend (correlation) if there is no
obvious pattern.
 If there is a trend, positive or negative, we can use the line of
best fit to make predictions.
POSITIVE
NO CORRELATION
NEGATIVE
HISTORY VS. MATH
 Here is a scatter plot showing the relationship between
students who took a History Test and a Math Test.
 Is there a relationship between the scores?
 Describe the relationship.
HISTORY VS. MATH
 Since there is a positive correlation with the data, predict
what a student who earned a 75% on their history test earned
on their math test.
 What can I draw that will help me make that prediction?
HISTORY VS. MATH
75% on
History
Test
 The line of best fit will help you make a prediction as to what
score the student would get on their math test if they earned
a 75% on their history test.
About 77%
 What score would he get on the math test?
POPULATION OF GOLDFISH & STAR FISH
 The following table shows the population between goldfish
and star fish at dif ferent aquariums.
Goldfish
13 18 19
20
27
16
22
24
32
12
Star Fish
30 25 20
15
12
28
18
13
10
29
 Is there a relationship in this data?
 What can we draw to see if there is a relationship?
 Draw a scatter plot 
GOLDFISH & STAR FISH
 Is there a relationship with this data?
 What kind of relationship is it?
 If I have a goldfish population of 15, how many star fish will
there be?
 What can I draw to help me make that prediction?
GOLDFISH & STAR FISH
 Draw a line of best fit.
 If I have a goldfish population of 15, how many star fish will
there be?
 There would be about 26 star fish.