P chart, Other Management

Assignment Help:

P Chart

As against the   668_p chart.png   and R charts which deal with quantitative aspects, these charts deal with the attributes which are qualitative factors possessed by the data. An example would be a person being a major or a minor or the marital status of the person. In these examples, we note that a person is either a major or not, similarly a person is either married or not. That is we are looking at whether the given data set is in confirmation with the given qualitatitive factor or not. The answer would be an emphatic yes or no and either a success or a failure. There is no neutral state of acceptance. In statistical process control, the data set which can take on only two values is called an attribute. From this point of view, it can  be said that the quality of the product conforms to the specified standards or it does not. Since we take into account the attributes of the given data set, the measure we will employ is the proportion of the data points satisfying the given criteria and the proportion of the data points that does not satisfy the criteria. With respect to this, let us recollect that the probability of success in the binomial distribution is denoted by "p" and the proportion of units that have a particular characteristic in a given population is symbolized by "p" and the same in a sample is denoted as   1038_p chart1.png  . Remember that using the binomial distribution to form interval estimates of a population proportion would be tedious and as the sample size increases the binomial distribution can be approximated by a normal distribution and therefore the number of successes are converted to the proportion of success by dividing np by n. Since np gives us the mean of the binomial distribution, the mean of the sampling distribution is given by np/n = p. q is used to denote the probability of failure and the proportion of units that do not show the characteristic under consideration. The standard deviation is also obtained on similar lines. That is, the mean and the standard deviation of the sampling distribution of the proportion are given by

2366_p chart2.png

With the fractional values of p and the center line at   1424_p chart3.png  , we plot the p chart. The control limits are given by

1647_p chart4.png

In case we do not know the p value, we estimate it by using the overall sample fractions. The mathematical expression for the same is shown below.

                    2183_p chart5.png   

where

          1502_p chart6.png       is the sample fraction in the j th interval of time

         k        is the sum of all the samples considered. 

Therefore in the equations given above to calculate lower and upper control limits, p should be replaced by   2438_p chart7.png  .

An important point to note is that if the value of LCL is below zero, we take the value of LCL as zero and if the value of UCL exceeds 1, it is considered as 1. Do you find any similarity between this concept and the concept of probability? Yes. If you recollect, the classical probability defines probability as the ratio of number of the outcomes where that particular event occurs to the number of all the possible outcomes. From this definition we can see the relationship between probability and the proportion of the units satisfying a particular characteristic out of all the units manufactured.

Then from the plot we identify the pattern and if required the corrective action is taken.


Related Discussions:- P chart

Discuss the sq3r technique of reading, Question 1 What do you mean by b...

Question 1 What do you mean by barriers of communication? Explain different types of barriers to communication 2 Explain the different types of listening 3 Discuss the SQ

Managing variability, McM Cog is a supplier of industrial parts.  Most orde...

McM Cog is a supplier of industrial parts.  Most orders are received at a call center. The call center currently has 10 phone lines total, i.e., a maximum of 10 callers may be in t

Describe the implementation of new technology, Question 1 Write a short no...

Question 1 Write a short note on technology strategy. Describe in brief about the innovation management Question 2 What is the significance of technology diffusion? What are

Types of sampling, TYPES OF SAMPLING: Sampling plans can be  grouped u...

TYPES OF SAMPLING: Sampling plans can be  grouped under two categories-probability  sampling and non-probability sampling. Probability sampling uses a technique by which the r

Outline the organisational and behavioural factors, Question 1: Describ...

Question 1: Describe what is meant by ‘skilled-based', ‘rule-based' and knowledge-based behaviour. Explain in each case how these operating levels can give rise to human error

Functional organisation - information centres, Functional Organisation: ...

Functional Organisation: The library is expected to take care of selection, acquisition and storage of documents. The documentation/information centre, in collaboration with t

Define business ethics, Question 1 i) Discuss managing quality transform...

Question 1 i) Discuss managing quality transformation in organisation ii) Explain the concept of quality in manufacturing & services Question 2 Explain the different step

Network configurations - cd rom network, Network Configurations   The b...

Network Configurations   The basic components of a single CD-Rom workstation are a microcomputer and a CD-ROM drive. A printer will be necessary if you want to obtain a paper c

Implementation of the project and assign a time frame, Government has decid...

Government has decided to construct a tunnel via le Pouce Mountain to provide an alternative access to Port Louis for road users coming from the east. Assuming that roads on both s

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd