Green Field Potatoes Co. sells a by-product of its potato processing operation, called a filter cake, to area feed-lots as cattle feed. Recently, the feedlot owners have noticed that the cattle are not gaining weight as quickly as they once were. They believe that the root cause of the problem is that the percentage of solids in the filter cake is too low. Historically, the percentage of solids in the filter cakes ran slightly above 12%. Lately, however, the solids are running in the 11% range. What is actually affecting the solids is a mystery, but something has to be done quickly. Individuals involved in the process were asked to identify variables that might affect the percentage of solids. This review turned up the six variables (in addition to the percentage of solids) listed below in the following table. Data collected by monitoring the process several times daily for 20 days are stored in the potatoes. xls file.
Assignment:
1. Thoroughly analyze the data and develop a regression model to predict the percentage of solids
2. Write an executive summary (1 page max) concerning your findings to the president of the Green Field Potatoes Co. Make sure to include specific recommendations on how to get the percentage of solids back above 12%.

A：Solids
B：pH
C：Lower Pressure
D：Upper Pressure
E：Cake Thickness
F：Varidrive Speed
G：Drum Speed Setting

A B C D E F G
9.7 3.7 13 14 0.250 6 33.00
9.4 3.8 17 18 0.875 6 30.43
10.5 3.8 14 15 0.500 6 34.00
10.9 3.9 14 14 0.500 6 34.00
11.6 4.3 17 18 0.375 6 36.24
10.9 4.2 16 17 0.500 6 31.76
11.0 4.3 16 19 0.375 6 34.00
10.7 3.9 15 16 0.375 6 32.13
11.8 3.6 8 8 0.375 6 37.00
9.7 4.0 18 18 0.500 6 36.00
11.6 4.0 12 13 0.313 5 45.00
10.9 3.9 15 15 0.500 5 50.00
10.0 3.8 17 18 0.625 5 46.91
10.3 3.8 13 14 0.500 4 57.50
10.1 3.6 17 17 0.625 4 60.40
9.9 3.8 17 18 0.500 4 53.14
9.5 3.5 17 18 0.625 6 34.40
10.5 3.8 15 17 0.500 6 33.96
10.8 3.9 15 17 0.750 6 35.00
10.4 3.9 14 15 0.500 6 35.00
10.9 4.0 15 16 0.500 6 34.00
11.2 4.4 17 19 0.375 6 34.00
9.5 3.8 17 17 0.500 6 33.49
10.7 3.9 15 17 0.500 6 33.38
10.1 3.8 15 17 0.500 6 41.00
10.5 3.8 17 17 0.500 6 36.00
10.9 4.0 15 17 0.250 6 34.00
15.5 4.3 13 15 0.625 6 41.00
13.1 4.0 17 17 0.500 6 35.00
11.0 4.0 14 15 0.375 6 36.00
12.5 4.2 15 17 0.313 6 37.72
11.7 4.2 14 14 0.250 6 36.00
11.9 4.4 15 16 0.375 6 36.52
11.7 3.4 8 10 0.313 6 38.08
17.8 4.3 12 12 0.313 6 38.00
11.8 4.5 14 15 0.250 6 33.00
10.0 3.7 12 13 0.250 5 48.00
10.3 3.7 15 15 0.500 5 48.00
9.8 3.8 14 15 0.500 5 47.24
10.0 3.7 13 14 0.500 6 37.00
10.6 4.1 14 15 0.500 6 33.70
11.2 3.9 13 14 0.375 6 38.26
10.9 3.7 13 14 0.313 6 38.00
11.0 4.1 13 14 0.375 6 37.00
11.0 4.1 14 15 0.375 6 38.00
11.7 4.5 14 14 0.250 6 36.26
11.8 4.4 13 14 0.250 6 37.45
12.0 4.2 13 13 0.375 6 38.00
11.8 4.6 14 14 0.375 6 36.90
11.1 4.0 14 15 0.500 6 37.00
11.6 3.9 14 14 0.500 6 37.50
11.0 4.0 14 15 0.500 6 36.00
11.2 3.9 15 15 0.313 6 35.00
11.0 4.2 14 14 0.375 6 37.00