Q. 4. A two year sales history by quarter for a seasonal product is given below.
Sales
Quarter First Year Second Year
1 30 42
2 48 58
3 60 74
4 35 44
a) Using Winter's method, forecast the quarterly sales for the third year.
b) Assume that the actual sales for the first quarter of year 3 is 48 units.
What is the revised forecast for the second quarter of the third year? Use a=?=?=0.2.
c) Assume the following actual sales occurred during third year.
Quarter Sales
1 48
2 70
3 95
4 50
What is the 95% confidence interval around a one-period forecast?