Questions: Question 4 0.83 pts Which one of the following characteristics is not required to conduct an independent-samples t test? a. The observations from the two samples must be independent. b. The number of groups needs to be two. c. Two samples are randomly selected from two populations. d. The two samples have equal variances.

Solution Steps

To conduct an independent-samples \( t \)-test, several characteristics must be satisfied:

1. The observations from the two samples must be independent.
2. The number of groups must be two.
3. Two samples must be randomly selected from two populations.
4. The two samples do not necessarily need to have equal variances; if the variances are unequal, Welch's \( t \)-test can be used.

Given the options provided in the question:

• a. The observations from the two samples must be independent. (Required)
• b. The number of groups needs to be two. (Required)
• c. Two samples are randomly selected from two populations. (Required)
• d. The two samples have equal variances. (Not required)

From the analysis, it is clear that option d is not a requirement for conducting an independent-samples \( t \)-test, as the test can be performed even when the variances of the two samples are unequal.

Final Answer