Sales Chapter3 Answers

13.                1985    2,413        -

                1986    2,407       -6

                1987    2,403       -4

                1988    2,396       -7

                1989    2,403        7

                1990    2,443       45

                1991    2,371      -77

                1992    2,362       -9

                1993    2,334      -28

                1994    2,362       28

                1995    2,336      -26

                1996    2,344         8

1. 2,384       40
2. 2,244    -140

        Yes!  The original series has a decreasing trend.

[pic 1]

[pic 2]

15.       a.         MPE

           b.         MAPE

   c.         MSE or RMSE

17.           = 4465.7            ∑ (Yt-1 − ) =  −2396.1      ∑ (Yt − )2 = 55,912,891

           ∑ (Yt − ) (Yt-1 − ) = 50,056,722                ∑ (Yt − ) (Yt-2 − ) =  44,081,598

           r1 =          = .895

        H0:  ρ1 = 0H1:  ρ1 ≠ 0

           Reject if t < -2.069 or t > 2.069

                SE([pic 3]) =[pic 4]= [pic 5]= [pic 6]= .204

                [pic 7] = [pic 8]= 4.39

           Since the computed t (4.39) is greater than the critical t (2.069), reject the null.