The following trend line and seasonal indices were calculate

The following trend line and seasonal indices were calculated from four weeks of daily sales.

Trend line:      y_t = 200 + 1.8t

Seasonal Effect:    

Day

Sunday

Monday

Tuesday

Wednesday

Thursday

Friday

Saturday

Seasonal Index

1.6

0.4

0.5

0.5

1.4

0.7

1.9

Forecast Saturday’s sales values for the next week.

Solution

Trend line:      yt = 200 + 1.8t

HERE, t = 1.90 and y is value on saturday

Accordingly, 1.90y = 200 + 1.80*1.90

y = 107.06

Sales would be 107.06 on Saturday