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 CSSBB candidate must determine sample size for a hypothesis test. Which factor, if increased, will REDUCE the required sample size?
Answer: Larger acceptable α level
A larger α (less stringent significance level) reduces the sample size needed because a wider rejection region is accepted.
Which hypothesis testing approach is most appropriate when testing whether a process proportion defective exceeds 2%?
Answer: One-proportion z-test
The one-proportion z-test compares an observed proportion to a specified target proportion.
After completing ANOVA and finding a significant F-statistic, which step is required to identify which specific group means differ?
Answer: Perform post-hoc pairwise comparisons (e.g., Tukey's HSD)
Post-hoc tests like Tukey's HSD identify which specific pairs of group means are significantly different after a significant ANOVA.
A Black Belt is analyzing whether a new machine reduces defect rate compared to the old machine. This is best framed as:
Answer: One-tailed test: H₁: μ_new < μ_old
When testing for a specific directional improvement (reduction), a one-tailed test in the direction of interest is appropriate.
The Mann-Whitney U test is the non-parametric equivalent of which test?
Answer: Two-sample independent t-test
Mann-Whitney U compares medians of two independent groups and is used when normality assumptions for the two-sample t-test are violated.
A Black Belt reports that their hypothesis test had 'low power.' Which of the following is a likely consequence?
Answer: Increased risk of Type II error (missing a real effect)
Low power (high β) means the test is unlikely to detect a true effect, increasing the risk of a Type II error.
A Six Sigma project team uses a significance level of α = 0.01 instead of α = 0.05. What is the trade-off?
Answer: Lower Type I error rate but higher Type II error rate
Lowering α makes it harder to reject H₀, reducing Type I errors but increasing the chance of Type II errors (missing real effects).