SPC Measurement System Analysis (MSA) 2

Question 1

In a 'crossed' Gauge R&R study design, what is the key characteristic?

Accepted Answer

Every operator measures every part multiple times

Answer

In a crossed design, every operator measures every part multiple times, allowing both repeatability and reproducibility to be fully estimated and separated.

Question 2

When is a 'nested' Gauge R&R design typically used instead of a crossed design?

Accepted Answer

When the measurement process is destructive and parts cannot be re-measured

Answer

Nested (or hierarchical) designs are used for destructive testing where each part can only be measured once, preventing the crossed design's repeated measurements.

Question 3

In a Gauge R&R ANOVA output, what does '%Contribution' represent?

Accepted Answer

The percentage of total observed variation attributable to each source (gauge, operators, parts)

Answer

%Contribution shows the proportion of total variance in the study that is attributable to each variation source such as repeatability, reproducibility, and part-to-part variation.

Question 4

What is the 'Number of Distinct Categories' (ndc) metric used for in a Gauge R&R study?

Accepted Answer

To indicate how many statistically distinct groups the measurement system can differentiate within the process variation

Answer

The ndc indicates the number of non-overlapping confidence intervals that can span the range of product variation, showing the measurement system's ability to distinguish between parts; a value of 5 or more is generally desired.

Question 5

What advantage does the ANOVA method provide over the Average and Range (X-bar & R) method in Gauge R&R analysis?

Accepted Answer

It can separate the operator-by-part interaction as a distinct source of variation

Answer

ANOVA can identify and quantify an operator-by-part interaction effect, which the Average and Range method cannot detect, providing a more complete picture of variation sources.

(SPC) Statistical Process Control Certification Practice Test

(SPC) Statistical Process Control Certification Practice Test

SPC Measurement System Analysis (MSA) 2