1. Homework 6 results

2. 1.aY = 150X + 200 Y = 200 + 150X Six minutes of flight... Y = 150*6 + 200 Y = 1100

3. 1.b. Car rental Y =.06X + 29 Y = 29 +.06X Rental for 200 miles... Y =.06 * 200 + 29 Y = $41.00

4. 2.a. Net loss of $20. Loss of $40 for membership plus $20 savings on $100 spent.

5. 2.b. SpendingSavings 0 0 10020 20040 30060 40080

6. 2.c.: Must spend $200 for membership to be worthwhile.

7. 2.d.: The function is linear because the change in Y is constant across all values of X. For every $100 spent, exactly $20 saved.

8. 2.e. Amount spent = X Amount saved = Y Y =.2X - 40

9. 3.a.Tobacco production

10. 3.b.Predicted 2012 production, equation method Y = -.0606 * 2010 + 122.28 Y = 0.353 billion pounds

11. 3.b. Predicted 2012 production, trendline extension method

12. 3.c.Confidence in prediction

13. Pro: Strong R-squared Near-term forecast Con: Imperfections in fit to trendline Possible shift in trend in last four years

14. 4.a. Percentage smokers

15. 4.b.Prediction of percentage smoking in 2010, equation method Y = -.4397 * 2010 + 902.23 Y = 18.4%

16. 4.b.Prediction of percentage smoking in 2010, trendline extension method

17. 4.d.Prediction of percentage smokers in 1953 Y = -.4397 * 1953 + 902.23 Y = 43.5%

18. 4.dConfidence in prediction

19. Pro: Strong fit, R-squared Con: Many years between 1953 and 1983, so many possible significant economic and social changes

20. 4.e.Prediction when 100 percent smokers 100 = -.4397 * X + 902.23 100-902.23 = -.4397 * X -802.23/-.4397 = X 1824 = X

21. 5.aMain point of article Projections of the percentage of the population who will be obese in 40 years is quite dubious if not totally bogus.

22. 5.b Relevance to linear models It makes exactly the same point about projections far into the future as we considered with regard to the number of motor vehicles and consumption of coal