The Department of Marine Resources reports the number of tonnes of pelagic fish caught off the west coast during each four-month period over four years as follows:
|
Period
|
2007
|
2008
|
2009
|
2010
|
|
Jan-Apr
|
44
|
45
|
38
|
40
|
|
May-Aug
|
36
|
42
|
32
|
31
|
|
Sep-Dec
|
34
|
34
|
27
|
28
|
(a) Calculate the three-period moving average trend of pelagic fish caught off the west coast.
(b) Plot the actual catches of pelagic fish and the moving average trend on the same graph. Comment on the pattern of pelagic fish catches over the past four years.
(c) Calculate the seasonal indexes for each of the four-month periods. Give an interpretation of each seasonal index.
(d) Find the least squares trendline for pelagic fish caught off the west coast for the past four years.
(e) Estimate the seasonally adjusted expected number of tonnes of pelagic fish to be caught off the west coast for each four-month period of 2011.