单项选择题

The mean and standard deviation of the net incomes for all companies making up a stock index is $ 3.5 million and $ 4. 2 million, respectively. If a random sample of 49 companies is taken from the index, the standard error of the sample mean is closet to:()

A. $85714.
B. $500000.
C. $600000.

题目列表

你可能感兴趣的试题

微信扫码免费搜题