SCO 3059 Chapter 8 Quiz

x-charts are used for: A]averages of variables data. B]individual attributes data. C]individual variables data. D]averages of attributes data.

individual variables data.

A precision parts manufacturer produces bolts for use in military aircraft. The specifications for bolt length are 37.50 ± 0.25 cm. The company has established an -chart and an R-chart using samples of size five. The center lines for the -chart and R-chart are set at 35.25 cm and 1.08 cm, respectively. What is the value of Cp for this process? Select one: a. 0.179 b. 1.333 c. 0.301 Incorrect d. 0.166

.179

A precision parts manufacturer produces bolts for use in military aircraft. The specifications for bolt length are 37.50 ± 0.25 cm. The company has established an -chart and an R-chart using samples of size five. The center lines for the -chart and R-chart are set at 35.25 cm and 1.08 cm, respectively. What is the value of Cp for this process? A]1.333 B]0.179 C]0.301 D]0.166

0.179

Pre-control

Green

C chart

Population will be a Poisson distribution, but applying the Central Limit Theorem allows us to assume a normal distribution for the sample statistics

Which of the following is NOT one of the basic applications of a control chart? A]To establish a state of statistical control. B]To calculate the average-range. C]To monitor a process to identify special causes of variation. D]To determine process capability.

To calculate the average-range.

Which of the following is a likely cause of the control chart pattern known as a "trend?" Select one: a. Aging equipment b. Maintenance schedules c. New process operator d. Sudden power surge

a

Collecting _____ data is usually easier than collecting _____ data because the assessment can usually be done more quickly by a simple inspection or count. A]variable; attribute B]conformances; nonconformances C]attribute; variable D]simple; complex

attribute; variable

A company wishes to monitor the variation in the length of time it takes to process and send a bill to a customer. Seven bills will be randomly selected each day for a 60-day period and the length of time it takes to process and send the bill to a customer will be recorded for each bill. The appropriate control chart is aNo: Select one: a. -chart. b. R-chart. c. p-chart. d. u-chart.

b

All else being constant, if the sample size in a p-chart increases from 100 to 120, the upper and lower control limits will: Select one: a. move farther apart. b. move closer together. c. not be affected. d. both shift upward.

b

If the variation in the process is due to common causes alone, the process is said to be: Select one: a. out of control. b. in statistical control. c. in pre-control. d. out of capability.

b

Process capability calculations make little sense if the process: Select one: a. data were taken over a period of time. b. is not in statistical control. c. variations are due to common causes. d. is not initiated.

b

Short repeated patterns in a control chart, with alternating high peaks and low valleys, are known as: Select one: a. trends. b. cycles. c. shifts. d. runs.

b

The output of a process is stable and normally distributed. If the process mean equals 23.5, the percentage of output expected to be less than or equal to the mean: Select one: a. is less than 25% . b. is 50%. c. is greater than 75%. d. cannot be determined without knowing the standard deviation value.

b

The s-chart is recommended when: Select one: a. the control chart calculations needs to be performed by hand. b. tight control of variability in the process is required. c. the -chart is not associated with an R-chart. d. the sample size for each sample needs to be reduced.

b

___ is measured as the amount of error in a measurement in proportion to the total size of the measurement. Select one: a. Precision b. Accuracy c. Systematic bias d. Capability

b

Because of high test costs, a sample of single wastewater sludge is tested daily for dissolved oxygen content. The appropriate control chart is: Select one: a. -chart and R-chart. b. u-chart. c. x-chart and moving range chart. d. x-chart and R-chart.

c

Compared to variable measurement, attributes measurement requires _____ to obtain the same amount of statistical information about the quality of the product. Select one: a. a more distributed population b. more nonconformances c. a larger sample d. a smaller sample

c

Control limits are often confused with _____. Select one: a. pre-control lines b. center lines c. specification limits d. three sigma limits

c

Which of the following is a major advantage of np-charts? Select one: a. They can be used for variable sample sizes. b. They are more accurate than p-charts. c. They are easier to understand for production personnel. d. The control limits are based on binomial distribution.

c

x-charts are used for: Select one: a. averages of variables data. b. individual attributes data. c. individual variables data. d. averages of attributes data.

c

A canning company defines a "nonconformance" as an orange juice can whose diameter is beyond the upper specification limit. A manager at the canning company wants to monitor the number of such orange juice cans produced per day. Each day, an employee will randomly select 120 cans over a period of four weeks. The employee then determines and plots the number of nonconformance cans in each sample. The appropriate control chart is aNo: Select one: a. u-chart. b. R-chart. c. p-chart. d. np-chart.

d

If the lower limit for a p-chart computes to a number less than zero, this indicates: Select one: a. that a calculation error has been made. b. that the process is out of control. c. that an attribute measure is incorrectly used. d. that the lower limit should be set at zero.

d

In service applications, the term _____ is generally used to describe a nonconformance. A]cycle B]unit C]error D]trend

error

The output of a process is stable and normally distributed. If the process mean equals 23.5, the percentage of output expected to be less than or equal to the mean: A]is less than 25%. B]is 50%. C]is greater than 75%. D]cannot be determined without knowing the standard deviation value.

is 50%

For variables data, the sample means are assumed to be: A]exponentially distributed. B]normally distributed. C]Poisson distributed. D]binomially distributed.

normally distributed.

If a process is neither capable nor in control, the appropriate first step is to: A]remove common causes of variation. B]redesign the equipment. C]remove special causes of variation. D]determine the process capability index.

remove special causes of variation.

A process is said to be out of control when: A]common causes are present. B]special causes are present. C]the process is not capable of meeting specifications. D]the upper and lower control limits cannot be computed.

special causes are present.

A _____ is the result of some cause that gradually affects the quality characteristics of the product and causes the points on a control chart to gradually move up or down from the center line. A]defect B]process shift C]cycle D]trend

trend