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:

Fatigue

Fatigue is a state of extreme tiredness or exhaustion, resulting from mental or physical exertion or illness.

Paradoxical Sleep

Another term for REM (Rapid Eye Movement) sleep, a phase of sleep characterized by dream activity, muscle paralysis, and rapid movement of the eyes.

N2 Sleep

A stage of sleep characterized by specific brain wave patterns known as sleep spindles and K-complexes, marking a deeper sleep than N1.

N1 Sleep

The initial stage of the sleep cycle, characterized by light sleep from which an individual can be easily awakened.