Hypothesis Testing Flashcards
7 cards from real Certified Six Sigma Black Belt Exam practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Hypothesis Testing flashcards as text
A Black Belt needs to test whether the variances of two process streams are equal before running a two-sample t-test. Which test is appropriate?
Answer: Levene's test or F-test
Levene's test or the F-test (variance ratio test) are used to compare variances of two groups.
In a hypothesis test, statistical power is defined as:
Answer: 1 − β
Power equals 1 − β, representing the probability of correctly rejecting a false null hypothesis.
A team performs a chi-square test of independence on a contingency table. What is the null hypothesis?
Answer: The two variables are independent
For a chi-square test of independence, H₀ states that the two categorical variables are independent (no association).
A manufacturer tests a new coating process and finds p = 0.048 with α = 0.05. A colleague argues the result is 'practically significant.' What is wrong with this reasoning?
Answer: Statistical significance does not guarantee practical significance
Statistical significance only indicates that an effect is unlikely due to chance; practical significance depends on the magnitude (effect size) of the difference.
When performing multiple hypothesis tests simultaneously, which risk increases?
Answer: Familywise Type I error rate
Running multiple tests inflates the familywise Type I error rate; corrections like Bonferroni are used to control it.
A Six Sigma team compares defect counts (discrete data) across four machine types. Which test is most appropriate?
Answer: Chi-square test of independence
Chi-square tests are used for categorical/count data to assess independence or differences across groups.
A Black Belt calculates a 95% confidence interval for the mean that does not include the hypothesized value μ₀. What does this imply?
Answer: Reject H₀ at α = 0.05
If the hypothesized value falls outside the 95% confidence interval, the two-sided hypothesis test rejects H₀ at α = 0.05.