SPC Data Collection & Interpretation 3

Question 1

A process produces shaft diameters measured to 0.001 inch. This is an example of:

Accepted Answer

Variable (continuous) data

Answer

Measurements on a continuous scale such as diameter are variable data, allowing infinite values within a range.

Question 2

When a gage is used to collect SPC data, gage R&R studies are conducted to assess:

Accepted Answer

Measurement system repeatability and reproducibility

Answer

Gage R&R quantifies how much of the observed variation comes from the measurement system itself (repeatability) versus different operators (reproducibility).

Question 3

In a histogram of process data, a bimodal shape most likely indicates:

Accepted Answer

Two distinct process streams or populations are mixed in the data

Answer

Two peaks in a histogram suggest that data from two different populations or process conditions have been combined.

Question 4

An operator collects 5 measurements every hour for 20 hours. The subgroup size (n) and number of subgroups (k) are:

Accepted Answer

n = 5, k = 20

Answer

Each hourly sample of 5 measurements is one subgroup, so n = 5 measurements per subgroup and k = 20 subgroups total.

Question 5

Which data collection error occurs when an inspector unconsciously rounds measurements toward a preferred value?

Accepted Answer

Bias or systematic error

Answer

Consistently rounding toward a value introduces a systematic bias that shifts all measurements in one direction.

(SPC) Statistical Process Control Certification Practice Test

(SPC) Statistical Process Control Certification Practice Test

SPC Data Collection & Interpretation 3