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Name
Class
Date
Practice
2-5
Form K
Using Linear Models
Make a scatter plot and describe the correlation. To start, plot the points.
1. (1, 2), (2, 4), (3, 7), (4, 6), (5, 9)
2. (1, 9), (2, 8), (3, 4), (6, 3), (8, 5)
Write the equation of a trend line, if possible.
3. (2, 1), (4, 5), (5, 4), (6, 6), (8, 8)
4. To begin, make a scatter plot and let x = 0 correspond to 1950.
Life Expectancy for People Born in Various Years
Year
1950
1960
1970
1980
1990
2000
2002
Life Expectancy
68.2
69.7
70.8
73.7
75.4
76.9
77.3
SOURCE: National Center for Health Statistics
5. The table below shows the average daily energy requirements for male children and
adolescents.
Daily Energy Requirements for Males
Age (years)
1
Energy needed 1100
(calories)
2
5
8
11
14
17
1300
1800
2200
2500
2800
3000
SOURCE: Go Figure: The Numbers You Need for Everyday Life
a. Use a calculator to find the line of best fit.
b. Use your linear model to predict how many calories a 19-year old needs per
day.
c. Use your linear model to predict the age of a male who needs 2300 calories per
day.
d. Reasoning Do you think this model also applies to adult males? Explain.
Prentice Hall Foundations Algebra 2 • Teaching Resources
Copyright © by Pearson Education, Inc., or its affiliates. All Rights Reserved.
45
Name
Class
2-5
Date
Practice (continued)
Form K
Using Linear Models
6. A woman is considering buying a car. She researches prices for various years of
the same model of car. The table below shows the data from her research.
Car Prices by Model Year
Model Year
Prices
2000
$5784
2001
2002
$6810
2003
$8237
$9660
2004
$10,948
a. Use a calculator to find the line of best fit. Let x = the number of years
since 2000.
b. Use your linear model to predict how much a 2007 model should cost.
c. Error Analysis She predicts that a 2005 model costs $9800. Does this seem
reasonable? Why or why not?
Consider each situation and predict the type of correlation you might find. Do
you think that changes in the first quantity caused the changes in the second
quantity?
7. a person’s weight and the size of clothing they wear
8. the number of rooms in a person’s home and the number of books a
person owns
9. the length of time a candle has been burning and the height of the candle
For each situation, find a linear model and use it to make a prediction.
10. A 2-mi cab ride costs $5.25. A 5-mi cab ride costs $10.50. How much does a 3.8-
mi cab ride cost?
11. There are 55 blades of grass in 1 in.2 of lawn. There are 230 blades of grass in 4
in.2 of the same lawn. How many blades of grass are in 3 in.2 of lawn?
12. An empty 5-gal water jug weighs 0.75 lb. With 3 c of water inside, the jug
weighs 2.25 lb. Predict the weight of the jug with 5 c of water inside.
Prentice Hall Foundations Algebra 2 • Teaching Resources
Copyright © by Pearson Education, Inc., or its affiliates. All Rights Reserved.
46