Which of the following is/are true?
I. Doubling every single value in a sample doubles the sample mean.
II. Adding a constant to each value in a sample leaves the mean unchanged.
III. The mean of a sample decreases as the number of observations increases.
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A. B. C. D. E. F.A
Adding a constant to each value in a sample increases the mean by the same constant. III is incorrect. As the number of observations increases, it is the expected difference between the sample mean and the population mean that decreases.