Two Independent Samples of Sizes 20 and 30 Are Randomly

question 142

Multiple Choice

Two independent samples of sizes 20 and 30 are randomly selected from two normally distributed populations. Assume that the population variances are unknown but equal. In order to test the difference between the population means, , the sampling distribution of the sample mean difference, , is:

• A) normal.
• B) Student-t with 50 degrees of freedom.
• C) Student-t with 48 degrees of freedom.
• D) None of these choices.

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Definitions:

P-Value

The likelihood of encountering test outcomes as significant as or more than the actual observed results, assuming the null hypothesis is valid.

Null Hypothesis

The proposition that observed differences among specific populations are attributed to errors in sampling or experimentation, hence indicating no major divergence.

Level Of Significance

The threshold chosen for deciding whether an observed effect is statistically significant, usually denoted by alpha.

Hypotheses

Plural form of hypothesis, which are propositions or statements made for the sake of argument that are tested through research and experimentation.