Attribute Sampling

Question 1

Which of the following is an attribute sampling standard?

A. ANSI/ASQ Z1.4
B. ANSI/ASQ Z1.9
C. MIL-STD-414
D. ISO 14001

Answer 1

A. ANSI/ASQ Z1.4

This is formally mil and it is used for attribute sampling whereas ANSI/asq 1.9 is used for variable sampling

Question 2

Which of the following is not a type of attribute sampling plan

A. Single sampling plan
B. Double sampling plan
C. Sequential sampling plan
D. Regression sampling plan

Answer 2

D. Regression sampling plan

Regression sampling is not a recognized type of attribute sampling, attribute sampling methods include single, double and sequential or multiple sampling

Question 3

Which inspection level is most commonly used in attribute sampling

A. Level I
B. Level II
C. Level III
D. S-4

Answer 3

B. Level II

Inspection level 2 is the default general inspection level offering a balanced approach between cost and quality detection

Question 4

What is the primary difference between inspection level 1 and inspection level 3

A. Level 1 ensure stricter quality control then level 3
B. Level 1 uses smaller sampling size than level 3
C. Level 3 is used only for continuous sampling
D. Level one applies to variable sampling in level 3 to the attribute sampling

Answer 4

B. Level one uses smaller sampling size than level 3

Level 1 is used for lower discrimination or if you were samples while level 3 is used for higher discrimination or more samples

Question 5

When would a company use special inspection levels s-1 to s-4

A. When normal inspection levels 12 and 3 are unavailable
B. When 100% inspection is mandatory
C. When reducing the number of lot rejections
D. When smaller sample sizes are needed due to cost or time constraints

Answer 5

D. When smaller sample sizes are needed due to the cost or time constraints

Special inspection levels s-1 to s-4 are used when similar, sample sizes must be used due to practical limitations

Question 6

What is the main advantage of single sampling plans

A. Reduced sample size compared to multiple sampling
B. Simplicity and ease of implementation
C. Higher discrimination between good and bad lots
D. Lower cost than doubling sampling

Answer 6

B. Simplicity and ease of implementation

Single sampling plans are straightforward to apply and are the most commonly used type of attribute sampling plans

Question 7

What is the main advantage of sequential sampling over single and double sampling plans

A. Fewer total samples are required on average
B. All defective items are automatically removed from the
C. The probability of acceptance is always 100%
D. It eliminates all defective products

Answer 7

A. Fewer total samples are required on average

Sequential sampling often requires fewer samples because decisions are made progressively reducing unnecessary inspections

Question 8

Which of the following correctly describes the main difference between mil-std-105 or ANSI/ asqz1.4 and Dodge – romig sampling plans

A. Dodge Omega plies only to single sampling while mil-std-105 applies only to double sampling
B. Mil always requires 100% inspection while Dodge roommate does not
C. MIL-Std-105 is based on aql while Dodge romeg focuses on LTPD and AOQL
D. Dodge romeg does not consider consumer risk while mil-std-105 does

Answer 8

C. Mil-Std-105 is based on aql while Dodge romig folk says on LTPD and AOQL

-105 which is now ANSI/asq z1.4 focuses on aql -based acceptance, whereas Dodge romig sampling is based on consumer risk ltpd and aoql

Question 9

What are the three types of inspection severity levels

A. High medium and low
B. Reduced normal and tight
C. Simple, double and multiple
D. Small, medium and large

Answer 9

B. Reduced normal and tight

The three inspection severity levels are reduced, normal and tight. Normal inspection is default starting level with reduced being less stringent and tight being more stringent

Question 10

When should switching from normal to tight inspection occur

A. When two out of five lots are rejected
B. When five consecutive lots are accepted
C. When production quality improves
D. When a lot is rejected

Answer 10

A. When two out of five consecutive lots are rejected

Switch from normal to tight inspection when two out of five consecutive lots are rejected on original inspection (switching rule)

Question 11

What conditions must be met to switch from normal to reduced inspection

A. 10 consecutive lots accepted
B. Production is steady and management approves
C. Both a and b
D. Either a or b

Answer 11

C. Both a and b

To switch to reduced inspections and consecutive lots must be accepted on original inspection. Production must be steady. Management must approve other conditions in the standard must be met

Question 12

What are the inspection levels in mil-std-105e/ansi? -Asq Z1.4

A. 1, 2, and 3only
B. S-1 s-2 s-3 s-4 only
C. 1, 2, 3, and s-1 through s-4
D. 1,2,3 and 4

Answer 12

C. 1, 2, 3. And s-1 through s-4

There are three general inspection levels, one two and three and four special inspection levels s-1 through s-4. Level 2 is the default unless otherwise specified

Question 13

What determines the sampling size code letter

A. Only lock size
B. Only inspection level
C. Both lot size and inspection level
D. Aql value

Answer 13

C. Both lot size and inspection level

The sample size code letter is determined by both the lot size the inspection level being used. 12, 3, or s-1 to s-4

Question 14

Forgiven sample size code letter what happens to the acceptance number as AQL become stricter or smaller

A. Increases
B. Decreases
C. Stays the same
D. Becomes a zero

Answer 14

B. Decreases

As aql becomes stricter, the acceptance number decreases for the same sample size code letter making the sampling plan more stringent

Question 15

When using the tables if an intersection point shows n = 50 AC = 2. Re = 3 what does this mean?

A. Except if less than or equal to two reject if greater than or equal to three
B. Except if less than two reject if greater than three
C. Except if equal to two reject if equal to three
D. Except if greater than or equal to two reject if less than or equal to three

Answer 15

A. Except of less than or equal to two reject if greater than or equal to three

For the sampling plan except the lot if less than or equal to two defects are found and reject the lot if greater than or equal to three defects are found. The sample size is 50 units

Question 16

If a cell in the table shows an arrow up, what does this indicate

A. Use the next lower sample size code letter
B. Switch to tightened inspection
C. Switch to the reduced inspection
D. Use the next higher sample size code letter

Answer 16

D. Use the next higher sample size code letter

And arrow up indicates you should use the sampling plan corresponding to the next higher sample size code letter in the same aql column

Question 17

And a double sampling plan with
first sample - N1 = 80 ac1 =2 re1 =5
Second sample - n2= 80 AC2 to = 6. Re2 = 7
If the first sample shows three defects? What action should be taken

A. Accept a lot
B. Reject the lot
C. Take second sample
D. Start over

Answer 17

C. Take second sample

For the first sample 3 defects is greater than the two acceptable limit but less than the five which fails the lot, so you would need to take a second sample

Question 18

Double sampling plan

First n 1. = 50 ac1 = 0 re1 = 3
Seconds. N2 = 50 AC. To = 4
If the first sample shows two defects and the second sample shows two defects, what is the decision

A. Accept the lot
B. Reject the lot
C. Take another sample
D. Use single sampling instead

Answer 18

B. Reject the lot

Total defects equal 2. + 2 = 4
Cumulative defects is four which is greater than or equal to two. Therefore, the lot must be rejected