A new industrial oven has just been installed. To test the temperatures of the oven, the inspector reads the temperature in the oven at four different places every half hour. The first reading, taken at 8 a.m., was 2040 degrees Fahrenheit. (Only the last two digits are given in the following table to facilitate computations.)
Reading
Time 1 2 3 4
8:00 a.m. 40 50 55 39
8:30 a.m. 44 42 38 38
9:00 a.m. 41 45 47 43
9:30 a.m. 39 39 41 41
10:00 a.m. 37 42 46 41
10:30 a.m. 39 40 39 40
A) Set up a mean chart. Mark the upper and lower control limits and the center line. Then plot the points. Interpret the chart.
B) Set up a range chart. Plot the ranges. Indicate the upper and lower control limits and the center line. Then plot the points. Interpret the chart.
The number of defects per unit in each of 10 samples is given below.
Unit Number of Defects Unit Number of Defects
1 2 6 2
2 1 7 2
3 0 8 4
4 2 9 3
5 3 10 5
C) Design a c bar chart. Indicate the upper and lower control limits and the center line. Then plot the points. Interpret the chart.
The number of defectives in each of 8 samples of n = 20 is given below.
Sample Number Defective Samples Number Defective
1 4 5 6
2 1 6 3
3 5 7 2
4 3 8 1
D) Design a percent defective chart. Indicate the upper and lower limits and the center line. Then plot the points. Interpret the chart.