Shipments (in tons) of welded tube by an aluminum producer are shown below:

Year 1 2 3 4 5 6 7 8 9 10 11

Tons 2 3 6 10 8 7 12 14 14 18 19

Required: -

(a)Graph the data, and comment on the relationship.

(b)Compute a 3-year moving average, plot it as a dotted line, and use it to forecast shipments in year 12.

(c)Using a weight of 3 for the most recent data, 2 for the next, and 1 for the oldest, forecast shipments in year 12.