An airline operates a call center to handle customer questio

An airline operates a call center to handle customer questions and complaints. The airline monitors a sample of calls to help ensure that the service being provided is of high quality. Ten random samples of 100 calls each were monitored under normal conditions. The center can be thought of as being in control when these 10 samples were taken. The number of calls in each sample of 100 not resulting in a satisfactory resolution for the customer is as follows:

Excel File: data19-09.xls

a. What is an estimate of the proportion of calls not resulting in a satisfactory outcome for the customer when the center is in control? Round your answers to three decimal places.

b. Construct the upper and lower limits for a p chart for the manufacturing process, assuming each sample has 100 calls. Round your answers to four decimal places. Enter negative values as negative numbers.

Solution

a) As estimate for proportion of calls not resulting in a satisfactory outcome is

pbar=sum(values)/*10*100=0.041

b) the control limts are given by

ucl=pbar+3sqrt(pbar*(1-pbar)/n)=0.1005

cl=pbar=0.041

lcl=pbar-3sqrt(pbar*(1-pbar)/n)=-0.0217