Home > CC3 > Chapter Ch7 > Lesson 7.3.2 > Problem 7-103
Marissa’s older sister was discussing purchasing a car with her summer job earnings. Marissa collected data from her friends at her job.
Refer to problem 7-92 for help.
Marissa would like to know the typical age of her friends’ cars. What kind of graphical display should she use?
A box plot shows center and spread of one-variable numerical data nicely.
Marissa wants to convince her dad that newer cars are more fuel-efficient. What kind of graph(s) should Marissa make to convince her dad?
Marissa wants to show her dad an association between age and fuel efficiency.
Make a scatterplot of the data.
Use age as the
-axis and fuel efficiency as the -axis.
Fully describe the association.
Weak, negative, linear association.
Draw a line of best fit on the data. Find the equation of the line of best fit.
Remember that when drawing a line of best fit, about half the points should be above the line and about half should be below.
Use the equation to predict what the correct fuel efficiency for a
-year-old car should be. You should get around
mpg.
Interpret the slope and
-intercept in this situation. A slope of
means that for each additional year old a car is, it is expected to go less miles per gallon.
What does the-intercept say about a new car?
Age of | Fuel Efficiency (mpg) |