Can the cost of flying a commercial airliner be predicted using regression analysis? If so, what variables are related to this cost? A few of the many variables that can potentially contribute are the type of plane, distance, number of passengers, amount of luggage/freight, weather condition, direction of destination, or even pilot skill. Suppose a study is conducted using only Boeing 737s traveling 800 km on comparable routes during the same season of the year. Can the number of passengers predict the cost of flying such routes? It seems logical that more passengers result in more mass and more baggage, which could, in turn, result in increased fuel consumption and other costs. Suppose the data displayed below are the cost and associated number of passengers for thirty-six 800-km commercial airline flights using Boeing 737s during the same season of the year. We will use these data to develop a regression model to predict cost by the number of passengers.
The data contains the data on the cost and number of passengers of 36 observations.
Cost Passengers
4.24 88
3.39 95
2.6 88
2.27 66
3.28 87
3.67 88
3.09 81
1.71 60
3.48 86
4.22 93
3.24 80
4.9 96
0.77 62
1.49 61
2.36 69
3.21 76
2.59 74
3.06 86
2.71 80
4.8 98
3.42 91
2.08 59
1.62 71
3.33 84
3.63 89
3.67 92
2.43 75
4.88 92
3.07 85
2.35 74
1.72 73
4.12 90
3.67 73
2.94 73
2.3 77
1.67 69
(a) Use software to estimate this model. Use three decimals in each of your least-squares estimates your answer.
Costi = ___ + ____numberofpassengersi
(b) Find the coefficient of determination. Express as a percentage, and use two decimal places in your answer.
r^2 =
(c) Find the standard deviation of the prediction/regression, using three decimals in your answer.
Se =
(d, i) You wish to test if the data collected supports the statistical model listed above. That is, can the cost of flying an 800-km commercial flight using Boeing 737s be expressed as a linear function of the number of passengers? Select the correct statistical hypotheses which you are to test.
A. H0: β0 = 0, HA: β0 < 0
B. H0: β0 = 0, HA: β0 ≠ 0
C. H0: β1 = 0, HA: β1 > 0
D. H0: β1 = 0, HA: β1 < 0
E. H0: β0 = 0, HA: β0 > 0
F. H0: β1 = 0, HA: β1 ≠ 0
G. H0: β0 ≠ 0, HA: β0 ≠ 0
H. H0: β1 ≠ 0, HA: β1 ≠ 0
(d, ii) Use the F-test to test the statistical hypotheses determined in (d, i). Find the value of the test statistic, using two decimals in your answer.
Fcalc =
(e, iii) Find the P-value of your result in (d, ii). Use three decimals in your answer.
P-value =
(e, iv) Use the t-test to test the statistical hypotheses determined in (d, i). Find the value of the test statistic, using three decimals in your answer.
Tcalc =
(e, v) Find the P-value of your t-test in (e, iv). Use three decimals in your answer.
P-value =
(f) Using an α of 5%, this data indicates that the cost of flying a commercial flight using Boeing 737s cannot be expressed as a linear function of the number of passengers.
(g) Find a 95% confidence interval for the slope term of the model, β1.
Lower Bound =
(use three decimals in your answer)
Upper Bound =
(use three decimals in your answer)
(h) Choose the correct interpretation of the meaning of your confidence interval for β1, in the context of the data.
A. As the cost of flying a commercial flight using Boeing 737s increases by 1 unit, the number of passengers increases by an amount that is somewhere between the lower and upper bounds found in (g).
B. There is a statistical relationship between the cost of flying a commercial flight using Boeing 737s and the number of passengers.
C. As the number of passengers increases by 1, the cost of flying a commercial flight using Boeing 737s increases by an amount that is somewhere between the lower and upper bounds found in (g).
D. There is no statistical relationship between the cost of flying a commercial flight using Boeing 737s and the number of passengers.
E. As the number of passengers increases by 1, the cost of flying a commercial flight using Boeing 737s will increase, on average, by an amount that is between the lower and upper bounds found in (g).
F. As the cost of flying a commercial flight using Boeing 737s increases by 1 unit, the number of passengers will increase, on average, by an amount that is somewhere between the lower and upper bounds found in (g).
(i) With 95% confidence, find the average cost of flying a commercial flight using Boeing 737s when the number of passengers is 70.
Lower Bound =
(use three decimals in your answer)
Upper Bound =
(use three decimals in your answer)