Twenty-five samples of 100 items each are inspected when a procedure is considered to be operating satisfatorily. In the 25 samples a total of 135 items are found to be defective.
a) Determine an estimate of the proportion defective when the process is in control?
b) Determine the standard error of the proportion if samples of size 100 will be used for statistical process control?
c) Calculate the upper and lower control limits of the chart