Question 1:

A company that makes car accessories. The company controls its production process by periodically taking a sample of 99 units from the production line. Each product is inspected for defective features. Control limits are developed using three standard deviations from the mean as the limit.

During the last 12 samples taken, the proportion of defective items per sample was recorded as follows:

0.01 0.03 0.0 0.04 0.01 0.01
0.00 0.01 0.02 0.02 0.03 0.03

a. Determine the mean proportion defective, the UCL, and the LCL? (Marks 1) (word count maximum:150)
b. Draw a control chart and plot each of the sample measurements on it? (Marks 1) (word count maximum:100)
c. Does it appear that the process for making tees is in statistical control? (Marks 0.5) (word count maximum:100)