Consider the following sales data measured in millions of dollars:

Period

Time Index

Actual Sales (millions)

1999Q1

1

12

1999Q2

2

18

1999Q3

3

20

1999Q4

4

12

2000Q1

5

12

2000Q2

6

20

aFind a four-period moving average for each quarter.

bFind the centered moving averages for the sample.

cFind the seasonal factors for Q3 and Q4 of 1999? Can you find the seasonal factor for 2000Q1?