问题如下:
BIM is a well-developed public company and its market capitalization growth rates over past few decades are normally distributed.The population has a mean of 10% and a standard deviation of 5.4%. An investor wants to figure out the probability that BIM's average capitalization growth rate will over 12.32% in the next three years (all the data are monthly statistics).Which of the following option is most accurate?
选项:
A.0.5%.
B.1%.
C.5%.
解释:
A is correct.
It is appropriate to use the central limit theroy to calculate.
The test statistic= (12.32%-10%)/0.009=2.58. So the corresponding probability is 0.5%.
实际算出来的test statistic为2.5778,比99%置信度的2.58小,会接受原假设。不应该选B吗?