SPC Fundamentals 5

Question 1

A scatter diagram is used in SPC primarily to:

Accepted Answer

Explore the relationship between two process variables

Answer

A scatter diagram plots pairs of variables to visualize potential correlations or relationships between them.

Question 2

Which of the following scenarios indicates that a process is 'in statistical control' but NOT 'capable'?

Accepted Answer

All points are within control limits but outside specification limits

Answer

A process can be stable (in control) yet still produce nonconforming output if its natural spread exceeds the specification range.

Question 3

The 'R chart' in an X-bar and R control chart monitors:

Accepted Answer

The range (spread) within each subgroup

Answer

The R chart tracks the within-subgroup range to monitor process variability over time.

Question 4

In a CUSUM (Cumulative Sum) chart, small persistent shifts in the process mean are detected:

Accepted Answer

More effectively than with a Shewhart X-bar chart

Answer

CUSUM charts accumulate deviations from the target over time, making them much more sensitive to small, sustained mean shifts than Shewhart charts.

Question 5

When establishing a new control chart, Phase I analysis refers to:

Accepted Answer

Collecting initial data, removing special causes, and calculating baseline control limits

Answer

Phase I is a retrospective analysis of historical data used to estimate process parameters and establish initial control limits.

(SPC) Statistical Process Control Certification Practice Test