The following table presentsquarterlyseasonal indexes for the number of new automobiles sold by a car dealership inLondonOntario.

Spring

Summer

Fall

Winter

1.15

0.80

1.10

0.95

a)Comment on theseasonal indexesin relation to automobile sales.(3 marks)

b)From the original historical data (2002 - 2006) a trend line ofTRt= 250 + 6t, where t = 1 to 20, was calculated. Assuming a multiplicative seasonal model forecast the number of new automobiles expected to be purchased in the year 2007, by quarter.(5 marks)