Basic Statistical Tools Flashcards
7 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 7 Basic Statistical Tools flashcards as text
In hypothesis testing, what does the p-value represent?
Answer: The probability of observing results as extreme as the sample if the null hypothesis is true
The p-value is the probability of obtaining the observed data (or more extreme) assuming the null hypothesis is true.
A Type II error in hypothesis testing occurs when you:
Answer: Fail to reject a false null hypothesis
A Type II error (β) means failing to detect a real effect — accepting H₀ when it is actually false.
What does a Cpk value of 1.33 indicate about a process?
Answer: The process is capable and has some margin relative to the nearest specification limit
Cpk = 1.33 is the traditional minimum target, indicating the process mean is at least 4σ from the nearest spec limit.
Which statistical test compares the means of exactly two independent groups?
Answer: Two-sample t-test
A two-sample t-test compares the means of two independent groups to determine if they differ significantly.
What is the interquartile range (IQR) used to measure?
Answer: The spread of the middle 50% of data
IQR = Q3 − Q1, capturing the spread of the central 50% of the data and resisting outlier influence.
A box plot whisker extends to a data point that is 1.7 × IQR above Q3. How should this point be classified?
Answer: A normal data point within the whisker
Box plot whiskers typically extend to 1.5 × IQR; 1.7 × IQR falls outside that but the point itself is still plotted at its actual value — it would actually be an outlier (mild) since 1.7 > 1.5.
Which type of variation in a process is attributable to identifiable, non-random causes?
Answer: Special cause variation
Special cause variation is assignable to specific, identifiable factors and is not part of the normal process distribution.