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lting the Model: The Least Squares Approach 631 11.22 Joint Strike Fighter progr

ID: 3052427 • Letter: L

Question

lting the Model: The Least Squares Approach 631 11.22 Joint Strike Fighter program. The Joint Strike Fighter 2) 1 (JSF) program, operated by the U.S. Department of F3s Defense, is a global defense program that involves ac- te al IS quisition of military fighter jets for participating allied countries. An article in the Air & Space Power Journal (March-April 2014) reported on the estimated annual cost of adding a military aircraft to the JSF program. The table below lists the year of initial operation and cost (in mil lions of dollars) for 12 JSF military aircraft models. For this probl initial operation for each aircraft model. a. Fit the simple linear regression model, Ely) lem, let y-estimated annual cost and x = year of A) + |x, to the data. y =-3,675 + 1.87x y-intercept of the line a military aircraft to the JSF program each year. (Hint: b. If possible, give a practical interpretation of the c. Give an estimate of the increase in the cost of adding Practically interpret the slope of the line.) $1.87 million Year Model Cost 40 1974 1975 1977 1978 1978 1979 1981 1987 1989 1998 2005 2012 F-14 F-15AB A-10 FA-18AB F-15CD F-16AB F-16CD FA-18CD F-15E FA-18EF F-22 F-35 28 13 26 30 16 20 29 31 105 80

Explanation / Answer

We use Minitab to solve this question.

Regression Analysis: Cost versus Year

Analysis of Variance

Source DF Adj SS Adj MS F-Value P-Value
Regression 1 6083.84 6083.84 26.35 0.000
Year 1 6083.84 6083.84 26.35 0.000
Error 10 2309.07 230.91
Lack-of-Fit 9 2301.07 255.67 31.96 0.136
Pure Error 1 8.00 8.00
Total 11 8392.92


Model Summary

S R-sq R-sq(adj) R-sq(pred)
15.1956 72.49% 69.74% 54.61%


Coefficients

Term Coef SE Coef T-Value P-Value VIF
Constant -3675 724 -5.08 0.000
Year 1.870 0.364 5.13 0.000 1.00


Regression Equation

Cost = -3675 + 1.870 * Year

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b)

Interpritation of intercept -

The intercept is -3675 indicates that when year of initial operation for each aircraft model is 0 then estimated annual cost is -6575 milions of dollars.

c) Interpritation of slope -

The slope is 1.87 indicates that when year of initial operation for each aircraft model changes with unity then estimated annual cost changes with 1.87 milions of dollars.