Certified Six Sigma Black Belt Exam Hypothesis Testing 3

Question 1

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?

Accepted Answer

Levene's test or F-test

Answer

Levene's test or the F-test (variance ratio test) are used to compare variances of two groups.

Question 2

In a hypothesis test, statistical power is defined as:

Accepted Answer

1 − β

Answer

Power equals 1 − β, representing the probability of correctly rejecting a false null hypothesis.

Question 3

A team performs a chi-square test of independence on a contingency table. What is the null hypothesis?

Accepted Answer

The two variables are independent

Answer

For a chi-square test of independence, H₀ states that the two categorical variables are independent (no association).

Question 4

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?

Accepted Answer

Statistical significance does not guarantee practical significance

Answer

Statistical significance only indicates that an effect is unlikely due to chance; practical significance depends on the magnitude (effect size) of the difference.

Question 5

When performing multiple hypothesis tests simultaneously, which risk increases?

Accepted Answer

Familywise Type I error rate

Answer

Running multiple tests inflates the familywise Type I error rate; corrections like Bonferroni are used to control it.

Certified Six Sigma Black Belt Exam Practice Test

Certified Six Sigma Black Belt Exam Practice Test

Certified Six Sigma Black Belt Exam Hypothesis Testing 3