When Testing the Difference Between Two Population Means Under Independent

question 30

Multiple Choice

When testing the difference between two population means under independent sampling, we use the z distribution if ________.

• A) the population variances are known
• B) the population variances are unknown, but assumed to be equal
• C) the population variances are unknown and cannot be assumed equal
• D) Both the population variances are known and the population variances are unknown, but assumed to be equal