Data Analysis & Reporting Flashcards

Which statistical measure is most useful for identifying the spread of process data around its mean?

Answer: Standard deviation

Standard deviation quantifies how much individual data points deviate from the mean, making it the primary measure of process spread.

A Lean team notices their defect rate data forms a J-shaped distribution. What does this most likely indicate?

Answer: Rare events dominate the data

A J-shaped distribution typically indicates rare-event data where most values cluster near zero with a long tail, common in defect counts.

What is the primary purpose of a control chart's upper and lower control limits (UCL/LCL)?

Answer: Indicate when a process has shifted to special cause variation

UCL and LCL are statistically derived at ±3 sigma to signal when special cause variation has entered the process.

In a Lean data reporting cadence, what is the recommended frequency for reviewing operational KPIs on a visual management board?

Answer: Daily at shift start or standup

Daily review of KPIs on visual management boards enables rapid detection and response to problems before they escalate.

A process capability index of Cpk = 0.85 tells a Lean analyst that:

Answer: The process does not meet the minimum capability threshold of 1.0

A Cpk below 1.0 indicates the process is not capable of consistently producing output within specification limits.

Which chart type is best suited for displaying the relative contribution of each defect category to the total defect count?

Answer: Pareto chart

A Pareto chart ranks defect categories by frequency with a cumulative percentage line, highlighting the vital few causes.

When conducting a measurement system analysis (MSA), a high % Gauge R&R result (>30%) suggests:

Answer: Measurement variation is excessive and the gauge needs improvement

A Gauge R&R above 30% means the measurement system contributes too much variation and will mask real process signals.