Q15. An analyst gathered the following information about a stock index:

Mean net income for all companies in the index                     $2.4 million

Standard deviation of net income for all companies in the index      $3.2 million

If the analyst takes a sample of 36 companies from the index, the standard error of the sample mean is closest to:

A. $66,667

B. $88,889

C. $400,000

D. $533,333

答案和详解如下：

Q15   D     07Modular Level I, Vol.1, PP 426-427    Study Session 3-10-e

The standard error of the sample mean is equal to the population standard deviation divided by the square root of the number of observations in the sample: $3,200,000/√36=$533,333.

Thanks

is it D?

thx