A population has standard deviation 20. For a random sample of 25 observations, what is the standard deviation of the sampling distribution of the sample mean?
Correct answer: B. 4
- A. 0.8
- B. 4
- C. 5
- D. 20
Explanation
The standard error of the sample mean is σ divided by the square root of n. Thus, it is 20/√25 = 20/5 = 4.
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