Problem 3.36 (Concluded)
The first regression equation has a very high R2; however, fixed cost is nega-
tive (but not significant) and the standard error is large. The multiple regres-
sion equation is much better. R2 is still very high (0.99), but all three variables
are significant. The fixed cost, while still not significant, is positive, and the
standard error is much smaller.
3. Y = $475 + $2.10(25,000) + $0.74(40,000) + $2.31(4,000)
= $475 + $52,500 + $29,600 + $9,240
4. Y = $475 + $2.10(25,000) + $0.74(40,000) + $2.31(2,000)
= $475 + $52,500 + $29,600 + $4,620
This result gives us more confidence in using the multiple regression. The
packing workers know that the number of fragile orders matters. Only the mul-
Problem 3.37
1. High: 1,800, $83,000
Low: 1,200, $52,000
V = (Y2 – Y1)/(X2 – X1)
= ($83,000 – $52,000)/(1,800 – 1,200)