Exam 21: Statistical Process Control

The lower and upper control limits of an control chart are usually set at:

Which of the following is NOT something you can do with an operating characteristic curve?

The process capability index measures the capability of the process to produce units whose dimensions fall outside the specification limits.

40 Samples Manufacturing ​ The mean of the sample means and the pooled standard deviation of 40 samples of size 5 taken from a production process under control are ,and S = 11.5,respectively. ​ ​ -{40 Samples Manufacturing Narrative} Calculate the centerline and control limits for the chart.

40 samples of size 800 were drawn from a manufacturing process and the number of defectives in each sample was counted.The mean sample proportion was .035.The lower control limit for the p chart is:

Assembly Line Random samples of 200 parts were taken on an assembly line every hour for the past 25 hours.The number of defective parts is shown in the accompanying table. ​ ​ -{Assembly Line Narrative} Construct the p chart.

When no point lies outside the control limits of a chart,we conclude that variation in the process is:

A predictable change in operators for the day shift and night shift can create assignable variation called a cycle.

30 Samples Production Thirty samples of size 4 were drawn from a production process.The data are shown below. ​ ​ -{30 Samples Production Narrative} Looking at the chart developed in a previous question,you see indications of a possible level shift as well as cyclic variation.Explain how the chart shows this,and give a possible explanation.

A hypothesis test is used to determine whether there is sufficient evidence to infer that the process mean has changed.This means H₀ is: the process is ____________________ control.

To determine whether the distribution mean of a process has changed,we use a(n)____________________ chart.

Variations in a process that are caused by specific events or factors that are frequently temporary and can usually be identified and eliminated are known as:

In order to ensure that a manufacturing process is under control,50 samples of size 1,000 were drawn and the number of defectives in each sample was counted.The mean sample proportion was .0234.Compute the centerline and control limits for the p chart.

If you change the control limits from ±3 standard errors from the centerline to ±2 standard deviations from the centerline,this ____________________ the probability of a Type I error and ____________________ the probability of a Type II error.

Sample proportions that are less than the lower control limit indicate a change in the process that we would like to make permanent.

What is the average run length (ARL)until an control chart signals a false alarm if the control limits are set at ±2 standard errors from the centerline?

Control charts that are used to monitor a process whose results are categorized as either defective or nondefective are called:

If a control chart finds six increasing or six decreasing points in a row,this is an example of assignable cause variation called a(n)____________________.

When the control chart shows a repeated series of small observations followed by large observations,the result is referred to as:

Describe what a Type II error is,and what its impact is,in terms of a production process.