Asked by Shayan Patel on May 03, 2024
Verified
A retail store manager is trying to improve and control the rate at which cashiers sign customers up
for store credit cards. After posting a p-chart of the store's credit card sign-ups the manager takes
new samples of size 50 three weeks later. He finds that each sample of 50 contained 5 credit card
signups on average. Find p-bar and 99.73% control limits.
Control Limits
Statistical boundaries set in process control that indicate the outer acceptable limits of variation in a process's performance.
- Evaluate and interpret the control limits and process capabilities for several control chart types like X-bar, R-chart, p-chart, and c-chart.
- Utilize the principles of 3-sigma for process control determination.
- Compute the mean and standard deviation for both individual samples and entire processes.
Verified Answer
ZK
Zybrea KnightMay 04, 2024
Final Answer :
P-bar = 5/50 = .1 or 10%. Sigma-p = sqrt(.1(1 - .1)/50) = .042426. z = 3 for the given confidence level. Using the equations for control limits gives
UCL= .1 + 3(.042426) = .22728
LCL= .1 - 3(.042426) = -.02728 and since a control limit cannot be negative round up to 0.
UCL= .1 + 3(.042426) = .22728
LCL= .1 - 3(.042426) = -.02728 and since a control limit cannot be negative round up to 0.
Learning Objectives
- Evaluate and interpret the control limits and process capabilities for several control chart types like X-bar, R-chart, p-chart, and c-chart.
- Utilize the principles of 3-sigma for process control determination.
- Compute the mean and standard deviation for both individual samples and entire processes.