Chapter 15 Statistical Quality Control

16) If we are attempting to control the diameter of bowling bowls, we will find a p-chart to be quite helpful.

17) A c-chart would be appropriate to monitor the number of weld defects on the steel plates of a ship's hull.

18) Which of the following is not a popular definition of quality?

A) Quality is the totality of features and characteristics of a product or service that bears on its ability to satisfy stated or implied needs.

B) Quality is defined as a competitively priced product that surpasses customer needs.

C) Quality is the degree to which a product conforms to design or specification.

D) Quality is fitness for use.

E) Even though quality cannot be defined, you know what it is.

19) Variations that need not occur in production processes are referred to as

A) assignable variations.

B) control variations.

C) natural variations.

D) process variations.

E) None of the above

20) Variations that usually occur in a process are called

A) process variations.

B) natural variations.

C) control variations.

D) assignable variations.

E) None of the above

21) A company believes a process monitored by an x-bar chart to be in control. When the most recent control point exceeded the UCL value by 20%, the company should

A) believe that a random bad luck chance occurred and proceed.

B) suspect that an assignable cause of variation now exists and can be found.

C) ignore the control point completely, as it is simply an outlier.

D) wait for the next four samples to be taken to see if a trend develops.

E) All of the above

22) Bags of pretzels are sampled to ensure proper weight. The overall average for the samples is 9 ounces. Each sample contains 25 bags. The standard deviation is estimated to be 3 ounces. The upper control chart limit (for 99.7% confidence) for the average would be ________ ounces.

A) 9.4

B) 18.0

C) 10.2

D) 7.2

E) 10.8

23) The inspection of cans of juice involves sampling some cans and weighing them. The overall average for the samples is 39 ounces. Each sample contains 36 cans. The standard deviation is estimated to be 2 ounces. The 99.7% lower control chart limit for the average would be

A) 37.67.

B) 38.00.

C) 39.33.

D) 40.00.

E) None of the above

24) Control charts that are used to monitor processes that are measured in continuous units are classified as which of the following?

A) Control charts for attributes

B) Control charts for variables

C) Control charts for defects

D) Control charts for quality

E) Control charts for sigma

25)-charts indicate changes in

A) variation.

B) central tendency.

C) natural variations.

D) numbers of defects.

E) None of the above

26) Who introduced control charts in 1924?

A) W. Edwards Deming

B) Philip Crosby

C) J.M. Juran

D) William Shewhart

E) Malcolm Baldrige

27) The-chart would be useful when we

A) took a number of measurements and computed the average.

B) took a number of measurements and computed the ranges.

C) found the fraction of the production lot defective.

D) found the number of defective items in a production lot.

E) None of the above

28) The R-chart would be useful when we

A) took a number of measurements and computed the average.

B) took a number of measurements and computed the ranges.

C) found the fraction of the production lot defective.

D) found the number of defective items in a production lot.

E) None of the above

29) R-charts measure changes in

A) central tendency.

B) degree of variation.

C) number of defects per production lot.

D) natural variations.

E) None of the above