Exam 13: Statistical Process Control

For large samples,and when data are analyzed by computer programs,the _____ is a better measure of variability.

Variable measurements are generally expressed as _____ and _____.

Which of the following is a major advantage of np-charts?

Common and special causes must be eliminated before process capability can be determined.

Six samples of size 10 were collected.The data are provided in the following table. The upper control limit (UCL)and lower control limit (LCL)for an s-chart are:

If the cost of investigating the cause of an apparent out-of-control situation is high,narrower control limits should be adopted.

A manager at a canning company wants to monitor the number of orange juice cans it produces each day that are beyond the upper specification limit for can diameter.Each day an employee will randomly select 150 cans and then determine and plot the number of cans that are beyond the upper specification limit for can diameter.The appropriate control chart is a(n):

Variation in process output can occur as a result of chance or as a result of assignable causes.

A c-chart is more appropriate than a u-chart if the nature of the process does not yield discrete measurable units of output.

A quality engineer took 40 samples of 100 transistors each from the output of an assembly line.Each transistor was tested and the number of defectives in each sample is recorded in the table below.Determine the control chart limits for a p-chart.

The acronym "SPC" stands for:

If a process is neither capable nor in control,the appropriate first step is to:

A precision parts manufacturer produces bolts for use in military aircraft. The specifications for bolt length are $37.50 \pm 0.25 \mathrm{~cm}$ . The company has established an $\bar{x}$ -chart and an $R$ -chart using samples of size five. The centerlines for the $\bar{x}$ chart and $R$ -chart are set at $37.65 \mathrm{~cm}$ and $1.03 \mathrm{~cm}$ , respectively. What is the value of $C_{p k}$ for this process?

If a unit of work has one or more nonconformances,we term the entire unit _____.

If the process mean and variance do not change over time,the process is considered to be:

A bank recently took 32 random samples of size 600 to determine the accuracy of its customer records.A customer record was considered to be nonconforming if any portion of the record was left blank.The sample data are presented below.Determine the control limits for an np-chart.

If the cost of a Type II error is low,narrower control limits should be selected.

The centerline for the np-chart is equal to the average number of nonconforming items per sample.

RM Industries wishes to monitor its end-of-week accounts receivable balance.To do so,the end-of-week balances for the previous 25 weeks were recorded and are shown below.Establish an x-chart and moving range (using n = 2)chart for this process.

A specification is 50.0 cm ± 10 cm.Sketch and label the pre-control zones for this specification.Put the following values on your sketch: nominal,upper and lower tolerance limits,and end points of the green zone.