QM 21-24

Question 1

What does the symbol “p” mean?

Answer 1

“p” is the proportion (friction) nonconforming in a single subgroup. It is posted to the chart but is not used to calculate the control limits

Question 2

What does the symbol “𝑝̅” mean?

Answer 2

“𝑝̅” is the average proportion (friction) nonconforming of many subgroups. It is the sum of the number nonconforming divided by the sum of the number inspected and is used to calculate the trial control limits

Question 3

What does the symbol “𝑝_0” mean?

Answer 3

“𝑝_0” is the standard or reference value of the proportion (friction) nonconforming based on the best estimated of 𝑝̅. It is used to calculate the revised control limits. It can be specified as a desired value.

Question 4

What does the symbol “𝜑” mean?

Answer 4

“𝜑” is the population proportion (friction) nonconforming. When this value is known, it can be used to calculate the limits, because 𝑃_0= 𝜑