The total number of overtime hours (in 1000s) worked in a large steel mill was recorded for 16 quarters, as shown below.
|
Year
|
Quarter
|
Overtime hours
|
|
1995
|
1
|
32
|
|
|
2
|
15
|
|
|
3
|
21
|
|
|
4
|
28
|
|
1996
|
1
|
35
|
|
|
2
|
16
|
|
|
3
|
27
|
|
|
4
|
29
|
|
1997
|
1
|
36
|
|
|
2
|
21
|
|
|
3
|
25
|
|
|
4
|
37
|
|
1998
|
1
|
41
|
|
|
2
|
29
|
|
|
3
|
31
|
|
|
4
|
40
|
a. Calculate the seasonal indexes based on the data set given above. (Note you need to develop the regression line first).
b. What do the seasonal indexes tell us?