Measure Phase: Data Analysis Flashcards
7 cards from real Lean Six Sigma Black Belt Certification practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Measure Phase: Data Analysis flashcards as text
A process engineer notices that a control chart shows 8 consecutive points on one side of the centerline. What does this pattern indicate?
Answer: A special cause shift in the process mean
Eight consecutive points on one side of the centerline is a Western Electric Rule violation indicating a special cause—likely a sustained shift in the process mean.
Which measure best describes the spread of the middle 50% of a data distribution?
Answer: Interquartile range (IQR)
The interquartile range (IQR) is the difference between the 75th and 25th percentiles, capturing the spread of the central 50% of data.
In regression analysis, what does a residual represent?
Answer: The difference between observed and predicted values
A residual is the difference between an observed data value and the value predicted by the regression model.
A Black Belt wants to compare the variance of two independent processes. Which statistical test is most appropriate?
Answer: F-test (Levene's or Bartlett's test)
The F-test (or Levene's/Bartlett's test) is used to compare the variances of two or more independent populations.
What is the primary purpose of a multi-vari chart in the Measure phase?
Answer: To identify the largest source of variation among positional, cyclical, and temporal families
A multi-vari chart graphically separates and compares positional, cyclical, and temporal sources of variation to identify the dominant family.
When a process has a Cpk of 0.85, what does this indicate?
Answer: The process is not capable of consistently meeting specifications
A Cpk below 1.00 indicates the process is not capable, meaning a significant portion of output falls outside specification limits.
Which type of data requires a p-chart for monitoring in statistical process control?
Answer: Proportion defective with variable subgroup sizes
The p-chart monitors the proportion of defective items in subgroups and accommodates variable subgroup sizes.