Lean Six Sigma Green Belt Basic Statistical Tools 1 Flashcards
6 cards from real Lean Six Sigma Green 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 6 Lean Six Sigma Green Belt Basic Statistical Tools 1 flashcards as text
In a normal distribution, approximately what percentage of data falls within two standard deviations of the mean?
Answer: 95.4%
The empirical rule states that ~68% of data falls within ±1σ, ~95.4% within ±2σ, and ~99.7% within ±3σ of the mean in a normal distribution.
A scatter diagram is primarily used to:
Answer: Identify the relationship between two continuous variables
A scatter diagram plots paired data points to visually reveal whether a relationship (positive, negative, or none) exists between two continuous variables.
Which of the following best describes a process capability index (Cp) value of 1.33?
Answer: The process is centered and highly capable
A Cp of 1.33 means the process spread fits within the specification limits with adequate margin (process width is 75% of the spec width), indicating a capable process. Cp does not account for centering—that is Cpk.
What does a p-value less than 0.05 indicate in hypothesis testing (assuming α = 0.05)?
Answer: The result is statistically significant and we reject the null hypothesis
When the p-value is less than the significance level α (0.05), the evidence against the null hypothesis is strong enough to reject it, meaning the result is statistically significant.
In a box plot (box-and-whisker plot), what does the line inside the box represent?
Answer: The median (50th percentile)
The line inside the box of a box plot marks the median (Q2 or 50th percentile). The box itself spans from Q1 (25th percentile) to Q3 (75th percentile), representing the interquartile range.
Which type of control chart is most appropriate for monitoring the proportion of defective items in a sample?
Answer: p-chart
A p-chart tracks the proportion (fraction) of nonconforming items per sample and is used for attribute data where each unit is classified as defective or not. The c-chart tracks the count of defects per unit, X-bar/R tracks continuous measurements, and I-MR is for individual continuous measurements.