Question

Siders Breakfast Foods Inc., produces a popular brand of raisin bran cereal. The package indicates it contains 24 oz of cereal. To ensure that the firm makes good in its marketing promo claim regarding box weight content, the Siders inspection department makes hourly check on the production process. As part of the hourly check, four boxes are selected and their contents weighed. The results for 25 samples are reported below.

Sample Number	Weight-1	Weight-2	Weight-3	Weight-4
1	25.1	24.4	25.6	23.2
2	23.2	23.9	25.1	24.8
3	25.6	24.5	25.7	25.1
4	22.5	23.8	24.1	25
5	23.2	24.2	22.3	25.7
6	22.6	24.1	20	24
7	23	26	24.9	25.3
8	24.5	25.1	23.9	24.7
9	24.1	25	23.5	24.9
10	25.8	25.7	24.3	26
11	24.5	23	23.7	24
12	25.1	24.4	25.6	23.2
13	23.2	24.2	23	25.7
14	23.1	23.3	24.4	24.7
15	24.6	25.1	24	25.3
16	24.4	24.4	22.8	23.4
17	25.1	24.1	23.9	26.2
18	24.5	24.5	26	26.2
19	25.3	24.5	24.3	25.5
20	24.6	25.3	25.5	24.3
21	24.9	24.4	25.4	24.8
22	23.2	24.2	22.3	25.7
23	24.8	24.3	25	25.2
24	23.2	24.2	23	25.7
25	24.8	24.3	25	25.2

1. Develop the appropriate control charts to evaluate and monitor the boxing process. Show work in excel.

2. What do the control charts tell you about the process during the 25-hour inspection period (i.e. Do a thorough interpretation and analysis of the charts.)?

Answer 1

a.

Calculatios

FOrmula used

b) The control charts state that the process is not in control as sample mean of sample 6 falls outside of control limits hence special cause variation should be removed and then the control limits should be recalculated after removing of the erroneous data