SPC Measurement System Analysis (MSA) 3

Question 1

What is 'resolution' (also called 'discrimination') in a measurement instrument?

Accepted Answer

The smallest detectable increment or unit the instrument can read

Answer

Resolution is the smallest increment that a measurement instrument can detect and display; insufficient resolution prevents the instrument from distinguishing small differences between parts.

Question 2

A rule of thumb in MSA states that an instrument's resolution should be no greater than what fraction of the process variation or tolerance?

Accepted Answer

1/10

Answer

The AIAG MSA Reference Manual recommends that the measurement increment (resolution) should be no larger than one-tenth (1/10) of the process variation or tolerance to avoid masking real differences.

Question 3

If a Gauge R&R study shows a high %GRR (e.g., 45%), which corrective action is most directly appropriate?

Accepted Answer

Investigate and reduce sources of measurement variation such as gauge wear, operator technique, or fixturing

Answer

A high %GRR means the measurement system contributes excessive variation; the corrective path is to identify and eliminate the root causes — gauge condition, operator method, environmental factors, or fixturing — not to change specifications or sampling.

Question 4

What does 'reproducibility' measure in a Gauge R&R study?

Accepted Answer

The variation in average measurements produced by different operators using the same gauge on the same parts

Answer

Reproducibility (Appraiser Variation) quantifies how much the measurement average changes when different operators use the same instrument to measure the same parts.

Question 5

In Attribute MSA, a 'miss rate' (false negative) occurs when:

Accepted Answer

An operator accepts a part that is actually defective

Answer

A miss (false negative / Type II error) occurs when the measurement system or appraiser incorrectly accepts a nonconforming part, allowing a defect to pass through uninspected.

(SPC) Statistical Process Control Certification Practice Test

(SPC) Statistical Process Control Certification Practice Test

SPC Measurement System Analysis (MSA) 3