Data Collection & Interpretation Flashcards

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

Answer: Variable (continuous) data

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

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

Answer: Measurement system repeatability and reproducibility

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

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

Answer: Two distinct process streams or populations are mixed in the data

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

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

Answer: n = 5, k = 20

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

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

Answer: Bias or systematic error

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

A Pareto chart is used during data interpretation to:

Answer: Identify the vital few defect categories that account for most problems

A Pareto chart ranks defect categories by frequency to apply the 80/20 rule and focus improvement efforts on the most significant issues.

Data collected in the order of production is called:

Answer: Time-ordered or sequential data

Time-ordered data preserves the sequence of production, which is essential for detecting trends and special causes on control charts.