Data We are interested in exploring the relationship between the weight of a vehicle and its fuel efficiency (gasoline mileage). The data in the table show the weights (in pounds), and fuel efficiency (in miles per gallon), for a sample of vehicles. Note the units here are pounds and miles per gallon. Weight(pounds) Fuel Efficiency (miles per gallon) 2695 25 2680 29 2730 38 3000 25 3410 23 3640 21 3700 27 3880 21 3900 19 4060 20 4710 15

1. Which variable should be the independent variable and which variable should be the dependent variable? Independent variable:________________________________ Dependent variable:___________________________________ 2. Graph. Draw a scatterplot of "weight" vs. "fuel efficiency", using a ruler or computer. Label both axes with words. Scale both axes (this means to write numbers on the axes). Draw the regression line (should be a straight line) on the same axes as your scatterplot. Be sure to turn this in with your project. 3. Numerical. Give the following values to 4 decimal places unless otherwise noted:

a) correlation coefficient b) regression line equation (HINT: use LinRegTTest, the line is of the form yhat = a + bx) c) p-value (HINT: use LinRegTTest) d) s (the standard deviation of |y - yhat|) (HINT: use LinRegTTest) e) SSE (sum of squared errors - you can calculate this directly or use the formula for s) f) The percent of variation in fuel efficiency can be explained by the variation in weight using the regression line.(Hint: Coefficient of determination) Give answer as percentage to 2 decimal places. g) For a car that has weight 3100 pounds, predict its fuel efficiency to 2 decimal places. Include units.

4. Is the correlation significant? Why or why not? (Answer in a complete sentence) 5. In a complete sentence, what is the practical interpretation of the slope of the least squares line in terms of weight and fuel efficiency? Your answer should include the numerical value of the slope of the line and correct units. 6. Can we predict the fuel efficiency of a car with weight 2000 pounds using the least squares line? Answer Yes or No then explain why or why not in a complete sentence. 7. Are there any outliers? ___________ (Answer yes or no) If so, which point (or points) is an outlier?