The ZenoFex is a manufacturer of electronic parts used in telecommunication industry. The demand for a special semiconductor produced in this firm in last 11 periods is given in Table 1.
Table 1 Semiconductor Demand in last 11 periods
|
Period
|
Semiconductor
|
|
1
|
48
|
|
2
|
55
|
|
3
|
59
|
|
4
|
61
|
|
5
|
66
|
|
6
|
70
|
|
7
|
73
|
|
8
|
78
|
|
9
|
86
|
|
10
|
89
|
|
11
|
93
|
The firm uses a production process in which the dimension of the semiconductor (in millimeter) is monitored using x-bar and R charts. 12 samples of n=3 observations have been gathered which are shown in Table 2.
Table 2 Sample Observations
|
Sample
|
Observation 1
|
Observation 2
|
Observation 3
|
|
1
|
26.6
|
24.8
|
25.2
|
|
2
|
27.2
|
26.6
|
26.2
|
|
3
|
25.7
|
27.3
|
25.9
|
|
4
|
26.2
|
28.3
|
28.2
|
|
5
|
25.9
|
24.6
|
16.4
|
|
6
|
28.2
|
26.6
|
25.9
|
|
7
|
24.5
|
27.3
|
24.5
|
|
8
|
26.6
|
28.3
|
26.1
|
|
9
|
27.3
|
28.3
|
26.6
|
|
10
|
28.3
|
24.6
|
27.3
|
|
11
|
24.6
|
26.6
|
28.3
|
|
12
|
26.5
|
27.3
|
24.6
|
According to the customer requirements all semiconductors with dimensions between 26 and 27 mm are acceptable. The process population is normally distributed.
Based on the above information answer the following questions:
a. Among the following three forecasting methods, which method should be used to forecast the demand for this product? Why?
- Simple moving average n = 3
- Exponential Smoothing with alpha = 0.4
- Exponential Smoothing with trend Adjustment (alpha = 0.2, beta = 0.4, T1 = 5, F1
= 49)
Note: Please show all calculation and graphs and explain the steps
b. Is the production process in control? Why?
c. Is the production process capable? Why?
d. What proportion of the production in this process will meet customer requirements?