Exam 19: Statistical Process Control

A quality analyst wants to construct a sample mean chart for controlling a packaging process.He knows from past experience that the process standard deviation is two ounces.Each day last week,he randomly selected four packages and weighed each.The data from that activity appear below. (a)Calculate all sample means and the mean of all sample means. (b)Calculate upper and lower 2-sigma x-bar chart control limits that allow for natural variations. (c)Based on the x-bar chart,is this process in control?

Consumer's risk is the probability of:

An operating characteristic (OC)curve describes:

Why do range charts exist? Aren't x-bar charts enough?

Acceptance sampling:

According to the text,what is the most common choice of limits for control charts?

Under which of the following situations will the average outgoing quality (AOQ)decrease?

What four elements determine the value of average outgoing quality?

Pierre's Motorized Pirogues and Mudboats is setting up an acceptance sampling plan for the special air cleaners he manufactures for his boats.His specifications,and the resulting plan,are shown on the POM for Windows output below.In relatively plain English (someone else will translate for Pierre),explain exactly what he will do when performing the acceptance sampling procedure,and what actions he might take based on the results.

The higher the process capability ratio,the greater the likelihood that process will be within design specifications.

A run test is used:

A retail store manager is trying to improve and control the rate at which cashiers sign customers up for store credit cards.Suppose the manager takes 10 samples,each with 100 observations.The p-bar value is found to be .05,and the manager does not want a lower limit below .0064.What z-value would this imply,and how confident can she be that the true lower limit is greater than or equal to .0064?

An acceptance sampling plan's ability to discriminate between low quality lots and high quality lots is described by:

The acceptable quality level (AQL)is the average level of quality we are willing to accept.

Which of the following is true regarding the relationship between AOQ and the true population percent defective?

Which of the following is TRUE regarding the average outgoing quality level?

Red Top Cab Company receives multiple complaints per day about driver behavior.Over 9 days the owner recorded the number of calls to be 3,0,8,9,6,7,4,9,and 8.What is the upper control limit for the 3-sigma c-chart?

Pierre's Motorized Pirogues and Mudboats is setting up an acceptance sampling plan for the special air cleaners he manufactures for his boats.His specifications,and the resulting plan,are shown on the POM for Windows output below.Pierre is a bit confused.He mistakenly thinks that acceptance sampling will reject all bad lots and accept all good lots.Explain why this will not happen.

What is the difference between the process capability ratio C_p and the process capability index C_pk?

The local newspaper receives several complaints per day about typographic errors.Over a seven-day period,the publisher has received calls from readers reporting the following total daily number of errors: 4,3,2,6,7,3,and 9.Based on these data alone,what type of control chart(s)should the publisher use?