Deck 9: Control Charts for Attributes

Question 1

When the lower limit of a c chart is less than zero:

A) change it to 0
B) recalculate; an error has been made
C)leave it alone
D)use a p chart

Answer 1

change it to 0

Question 2

Which of the following concerning the p chart is false?

A) it is a variable control chart
B) can give an overall quality picture
C) can be used for many characteristics
D) evaluates the CEO

Answer 2

A

Question 3

A u chart measures:

A) the number of nonconforming units
B) the count of nonconformities
C) the number of standard deviations
D) the count of nonconformities/unit

Answer 3

D

Question 4

Trial control limits are calculated based on at least:

A) 5 subgroups
B) 25 subgroups
C) 15 subgroups
D) 35 subgroups

Question 5

Which of the following is not a purpose of p charts?

A) to discover the average quality level.
B) to discover low spots which may be due to erratic inspection or superior quality.
C) to suggest places to use X and R charts
D) none of the above

Question 6

Determine the revised central line for a count of nonconformities chart. Assume any out-of-control points have assignable causes. Data not shown are in control. The trial central line is 0.80, the trial UCL is 2.00, and the trial LCL is 0.

Question 7

A np chart is used for:

A) controlling the number of nonconformities of a product
B) controlling the fraction nonconforming in a lot
C) cases where there are few opportunities for a nonconformity to occur
D) controlling the number nonconforming of a product

Question 8

Determine the trial UCL and trial central line for a count of nonconformities chart for 25 subgroups where the sum of the count of nonconformities is 3827.

Question 9

A fraction nonconforming chart is frequently converted to a percent nonconforming chart:

A) so that employees can understand it better
B) because of the difficulty of variable subgroup size
C) so that an average subgroup size (n) can be used
D) so that the lower control limit will be eliminated

Question 10

The severity problem of a quality characteristic can be minimized by:

A) an alert inspector
B) using two-sigma limits
C) demerit system
D) none of these

Question 11

The problem of variable subgroup size for a p chart can be minimized by:

A) using an average subgroup size
B) changing the product
C) changing the production process
D) none of these

Question 12

Determine the trial UCL for a fraction nonconforming chart for May 8 where the trial central line is 0.012. Is May 8 in control or out of control and why?

Question 13

A p chart is used for:

A) controlling the count of nonconformities in a product
B) controlling the fraction nonconforming
C) cases where there are few opportunities for nonconformities to occur
D) none of these

Question 14

A process is in statistical control. Ninety-five pieces are inspected every day and the population percent nonconforming is 7.2%. What is the UCL of a number nonconforming chart?

Question 15

Which of the following concerning the p chart is true:

A) applied to quality characteristics which are variables
B) gives a poor overall quality picture
C) can be used for many characteristics
D) all of the above

Question 16

The first five steps of the control chart process are for:

A) the operators
B) the supervisors
C) planning
D) action