13.20 Less Red Meat! Canadians are very vocal about their attempts to improve personal well-being by "eating right and exercising more." One desirable dietary change is to reduce the intake of red meat and to substitute poultry or fish. Researchers tracked beef and chicken consumption, Y (in annual kilograms per person) and found the consumption of beef declining and the consumption of chicken increasing over a period of seven years. A summary of their data is shown in the table.

Consider fitting the following model, which allows for simultaneously fitting two simple linear regression lines:

a. How well does the model fit? Use any relevant statistics and diagnostic tools from the printout to answer this question.

b. Write the equations of the two straight lines that describe the trend in consumption over the period of seven years for beef and for chicken.

c. Use the prediction equation to find a point estimate of the average per-person beef consumption in year 8. Compare this value with the value labelled "Fit" in the printout.

d. Use the printout to find a 95% confidence interval for the average per-person beef consumption in year 8. What is the 95% prediction interval for the per-person beef consumption in year 8? Is there any problem with the validity of the 95% confidence level for these intervals?

Transcribed Image Text:

Year Beef Chicken 1 -234567 85 89 581 37 36 76 47 76 47 68 62 67 74 60 79