1. The following data was collected randomly from a production process of medical pouches. The following Burst Strength (in H2O) data were recorded.
26.7 24 25.8 29.2 28.6
23.1 27.7 26.6 28.9 30.7
29 27.2 24.6 28.5 27.8
28 24 30.9 31.7 24.2
23.1 29.8 30.3 22.2 27.1
A. Display the data graphically by constructing
i. Stem and Leaf Plot
ii. Boxplot
iii. Histogram of the data
2. Data was collected from a textile finishing process. Samples were collected daily and the number of nonconformities were recorded. (recall more than one nonconformity can be present on each unit)
Day Number of units
produced
Number of
Nonconformities
1 13 60
2 12 43
3 19 55
4 14 44
5 18 55
6 13 40
7 24 61
8 15 49
9 16 66
10 11 41
a. Construct an appropriate control chart for the above data.
b. Do any of the points exceed the 3 sigma control limits?
3. The following data was collected from a manufacturing line. Five samples are taken at random periodically and tested for a particular quality characteristic.
X1 X2 X3 X4 X5
20.3 22.4 23.0 22.3 21.6
19.9 21.6 20.5 20.1 19.3
23.6 21.3 22.7 22.4 20.7
21.1 20.0 18.9 21.0 19.4
23.5 18.0 22.8 20.1 20.7
17.9 20.0 19.2 20.8 21.4
22.7 23.8 23.1 22.0 21.8
21.9 22.7 21.7 22.5 20.4
19.5 20.6 22.0 20.5 19.5
20.5 22.3 23.6 22.4 21.5
20.9 18.6 17.9 18.1 19.7
20.2 21.0 21.2 20.6 21.2
20.1 20.1 21.4 22.6 20.1
20.9 19.4 17.0 22.4 21.0
19.0 22.0 15.9 21.3 21.6
a. Construct either an X-bar and R chart or an X-bar and S chart on the process.
b. Estimate the process standard deviation.
c. Plot the charts. Applying the western electric rules, is the process in Statistical Control?
4. A particular manufacturing process is monitored by sampling one at a time (subgroup size = 1). The individual data from the last 30 points are given below:
Sample X Sample X
1 43.5 16 38.0
2 38.1 17 34.0
3 38.7 18 41.0
4 42.0 19 39.1
5 39.3 20 41.5
6 38.8 21 39.7
7 38.3 22 40.5
8 41.8 23 39.8
9 41.9 24 41.6
10 39.0 25 42.9
11 38.3 26 43.0
12 40.1 27 41.3
13 41.0 28 37.0
14 34.4 29 39.5
15 36.5 30 41.4
a. Construct an Individuals chart
b. Construct a MA Chart
c. Construct either a Cusum or EWMA chart