Question

discuss the purpose of control charts, how they are created, what calculations are used, and why...

discuss the purpose of control charts, how they are created, what calculations are used, and why they are important in measuring quality. Then, create a control chart based on criteria that you come up with and explain it.

Homework Answers

Answer #1

Control charts are graphs that are used to study the changing of processes over time. They can also be used to predict the future performances of the said process. Control charts are mainly used for time-series data and logically comparable data. The data are plotted in chronological order.

There are two kinds of control charts:-

  • c control chart: where ‘c’ represents no. of non-conformances within one subgroup
  • u control chart: where ‘u’ represents no. of non-conformances per unit within one subgroup

A control chart consists of an upper line for upper control limit (UCLc), a lower line for lower control limit (LCLc) and a central line for the average. The UCLc and LCLc can be calculated as follows:-

where,

Example:-

Suppose we have to track the no. of burgers sold by a fast food joint on a monthly basis. The fast food joint is the area of opportunities for sales to occur. We have to collect the data each month on the no. of burgers sold. Once, enough data is available, we can calculate UCLc and LCLc.

Month No. of Burgers (c)
Jan-17 220
Feb-17 157
Mar-17 170
Apr-17 135
May-17 142
Jun-17 178
Jul-17 241
Aug-17 163
Sep-17 121
Oct-17 194
Nov-17 172
Dec-17 219
Jan-18 156
Feb-18 145
14

2413 ----> Total

c bar = Sum of no. of burgers/ no. of months = 2413/14 = 172.36

UCLc = 172.36 + (3* (square root of 172.36)) = 211.74
LCLc = 172.36 - (3* (square root of 172.36)) = 132.97

There should be two lines drawn on graph - one at UCL = 211.74 and the other at LCL = 132.97.

Distinct causes of variation are detected on control charts by observing definite types of patterns that appear on the control chart. The points beyond the UCLc and LCLc is one such pattern. These kinds of patterns indicates that something has happened to cause the process average go up or down, that is, a special cause is present. Identifying patterns and what they refer to in the process is one crucial to reason for special causes. All the control chart patterns that form on the control chart indicate special causes of variation that are present.

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
What is a control chart? How is it used? What are the benefits of using control...
What is a control chart? How is it used? What are the benefits of using control charts? Describe three fundamental principles regarding the statistical basis of control charts and why these principles are important
Control charts for x bar and R with subgroup size=4 are used to monitor a normally...
Control charts for x bar and R with subgroup size=4 are used to monitor a normally distributed quality characteristic. The control charts parameter were: X bar chart UCL=813, x bar chart CL=800, x bar chart LCL=787. R chart UCL=46.98, R chart CL=20.59, R chart LCL=0, both charts exhibit control. If the process mean shift from 800 to 780. What is the probability of detecting this shift on or before the second sample? A. 0.9934 B. 0.9834 C. 0.9993 D. 0.9894...
Using Control Charts for Improving Healthcare Quality The National Health Service (NHS) in the United Kingdom...
Using Control Charts for Improving Healthcare Quality The National Health Service (NHS) in the United Kingdom makes extensive use of SPC charts to improve service delivery to patients. SPC charts are frequently developed using Excel spreadsheets. Employees throughout NHS attend a two-day training course where they learn about X- and R-charts and their application. They also learn about Deming’s 14 points and principles of quality management and how to improve processes in their own operation. The number of possible applications...
What is the purpose of PCR? Why is Taq polymerase used in PCR? Where does it...
What is the purpose of PCR? Why is Taq polymerase used in PCR? Where does it come from?
Presenting Data (Bar Charts) [LO-3] Team up with a classmate to design charts based on a...
Presenting Data (Bar Charts) [LO-3] Team up with a classmate to design charts based on a comparison of the total tax burden of the U.S. taxpayer with that of people in other nations (see the data following this paragraph). One teammate should sketch a horizontal or vertical bar chart, and the other should sketch a pictogram from the estimates that follow. Then exchange charts and analyze how well each conveys the situation of the U.S. taxpayer. Would the bar chart...
What is the purpose and philosophy of quality improvement or assessment? Why is there is such...
What is the purpose and philosophy of quality improvement or assessment? Why is there is such an emphasis on patient safety in today’s healthcare environment? Discuss how risk management is related to the other components of quality. Outline the focus of several quality watchdog groups and government agencies promoting patient safety and quality improvement. Differentiate between the basic components of a risk management program.
Explain why stratification is used in holdout estimation. What purpose does it serve?
Explain why stratification is used in holdout estimation. What purpose does it serve?
What is the purpose of performance appraisals? How would you measure a nurse’s productivity? Discuss the...
What is the purpose of performance appraisals? How would you measure a nurse’s productivity? Discuss the multiple forms that violence can take within the workplace. Why is violence prevalent in a health care environment?
What is the purpose of performance appraisals? How would you measure a nurse’s productivity? Discuss the...
What is the purpose of performance appraisals? How would you measure a nurse’s productivity? Discuss the multiple forms that violence can take within the workplace. Why is violence prevalent in a health care environment?
What is the purpose of performance appraisals? How would you measure a nurse’s productivity? Discuss the...
What is the purpose of performance appraisals? How would you measure a nurse’s productivity? Discuss the multiple forms that violence can take within the workplace. Why is violence prevalent in a health care environment?
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT
Active Questions
  • Statistics Discussion: The accuracy of a forecasting technique is evaluated especially using the MSE (mean squared...
    asked 42 minutes ago
  • If the U.S. government manages to close a recessionary gap and achieve potential GDP with fiscal...
    asked 47 minutes ago
  • A block with mass 10kg is on a ramp angled at 20 degrees above the horizontal,...
    asked 47 minutes ago
  • I have a sample of 31 7thgrade girls who took an IQ test.  I calculated the sample...
    asked 54 minutes ago
  • A researcher wishes to estimate the proportion of adults who have​ high-speed Internet access. What size...
    asked 54 minutes ago
  • Brick column in the external corridor of a house, with section size of 440 mm X520...
    asked 55 minutes ago
  • 17.                             Mel has a(n) __________ lien on Ellen’s car after he replaced her clutch. The lien.
    asked 1 hour ago
  • Jackson Company engaged in the following investment transactions during the current year. Feb 17,Purchased  430 shares of...
    asked 1 hour ago
  • When might discrimination in the workplace be justified? Might discrimination on the basis of gender or...
    asked 1 hour ago
  • The strength grade of materials used for brick masonry at a certain site is as follows:...
    asked 1 hour ago
  • Show (prove), from the original definition of the integers, that subtraction of integers is well defined....
    asked 1 hour ago
  • How is polarity of a "bond" different than polarity of a "molecule?" What makes a particular...
    asked 1 hour ago