Refer to Problem 27. The default multiplicative decomposition in Minitab assumes a linear trend. Fit and plot a linear trend line to the Wal-Mart sales. Is a linear trend appropriate for these data? If not, can you suggest a trend curve that might be appropriate? Fit your suggested trend curve and store the residuals. Compute the residual autocorrelations. Do the residual autocorrelations suggest a seasonal component? Explain.

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TABLE P-27 Quarter Year 1990 1991 1992 1993 1995 1996 1997 1998 1999 2000 2001 2002 2003 6,768 9.281 11,649 13,920 17,686 20,440 22.772 25.409 29,819 35,129 43.447 48,565 52,126 57.224 65,443 7,544 10,340 13,028 16,237 19,942 22,723 25,587 28,386 33,521 28,913 46,588 53,187 56,781 63.231 70,466 7,931 10,628 13,684 16,827 20,418 22,914 25,644 28,777 33.509 40,899 46,181 53,185 55,765 63,036 69,261 10,359 13,639 17,122 20,361 24,448 27.550 30,856 35,386 40.785 51,868 57,079 64.735 66,905 75,190 82.819 0