Fuel efficiency can make a big difference in the operating cost of your car. The following table gives the fuel economy for selected 1995 two-seater cars along with the average annual fuel cost to operate the car. Make and Model of Car Estimated mpg (city) Annual fuel cost Chevy Corvette 17 900 Dodge Viper 13 1266 Honda Del Sol 29 562 Honda NSX 18 1012 Mazda MX-5 Miata 22 751 Mercedes Benz SL 320 17 1012 Nissan 300 ZX 18 1012 Suzuki X-90 2WD 25 693   Source: Consumers’ Research Magazine, Nov. 1995 v.78     Would you expect that there would be a relationship between these two quantities? Explain.   YES    or   NO     (circle one)   Why?           If the relationship was linear, would you expect it to be a positive or negative correlation?    POSITIVEorNEGATIVE     (circle one)   Why?           Name the independent and dependent variables.   independent variable (x): _________________________     dependent variable (y): ___________________________     Using your calculator or computer software, scatterplot the data points. Sketch the graph below. Label the axes with what each represents and show a numerical scale on each.                                    Does the relationship look linear?      YES    or    NO    (circle one)   Find the least squares regression line. Write the model:  (Round to three decimal spaces)   Sketch the line on your graph in #4.     What is the correlation coefficient R?   What does it tell you about the relationship between the gas mileage and average annual fuel cost? (describe the correlation using: weak positive, moderate positive, strong positive, weak negative, moderate negative, or strong negative)       Do you think the variables have a cause and effect relationship?     YES   or  NO  (circle one)   Why?         Use the regression line to predict the average annual fuel cost for cars that have a gas mileage of 20 mpg and 38 mpg.    Predicted fuel cost for 20 mpg: ____________________   Predicted fuel cost for 38 mpg: ____________________   Which prediction do you have more faith in?    20 mpg        or   38 mpg   (circle one)   Why?               Describe what the slope means in terms of the problem situation.   As x increases by one, y (decreases / increases) by _________________.  (circle one)(how much)   SO   As the ________________increases by one mpg, the ___________________ (decreases / increases)    (independent variable)       (dependent variable)              (circle one)   by _________________.  (how much)     Does the vertical intercept (y-intercept) make sense in terms of the situation?    YES or  NO   (circle one)     Why?

Fuel efficiency can make a big difference in the operating cost of your car. The following table gives the fuel economy for selected 1995 two-seater cars along with the average annual fuel cost to operate the car.

Source: Consumers’ Research Magazine, Nov. 1995 v.78

1. Would you expect that there would be a relationship between these two quantities? Explain.

YES    or   NO     (circle one)

Why?

1. If the relationship was linear, would you expect it to be a positive or negative correlation? 

POSITIVEorNEGATIVE     (circle one)

Why?

1. Name the independent and dependent variables.

independent variable (x): _________________________

dependent variable (y): ___________________________

1. Using your calculator or computer software, scatterplot the data points. Sketch the graph below. Label the axes with what each represents and show a numerical scale on each. 

1. Does the relationship look linear?      YES    or    NO    (circle one)

Find the least squares regression line. Write the model: 

(Round to three decimal spaces)

Sketch the line on your graph in #4.

1. What is the correlation coefficient R?

What does it tell you about the relationship between the gas mileage and average annual fuel cost? (describe the correlation using: weak positive, moderate positive, strong positive, weak negative, moderate negative, or strong negative)

1. Do you think the variables have a cause and effect relationship?     YES   or  NO  (circle one)

Why?

1. Use the regression line to predict the average annual fuel cost for cars that have a gas mileage of 20 mpg and 38 mpg. 

Predicted fuel cost for 20 mpg: ____________________

Predicted fuel cost for 38 mpg: ____________________

Which prediction do you have more faith in?    20 mpg        or   38 mpg   (circle one)

Why?

1. Describe what the slope means in terms of the problem situation.

As x increases by one, y (decreases / increases) by _________________. 

(circle one)(how much)

SO

As the ________________increases by one mpg, the ___________________ (decreases / increases) 

  (independent variable)       (dependent variable)              (circle one)

by _________________. 

(how much)

1. Does the vertical intercept (y-intercept) make sense in terms of the situation? 

YES or  NO   (circle one)

Why?