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%.
这道题目算出来的 test statistic接近2.58,即99%的区间,为什么不是单边假设,即H0<12.3..%,这里为什么是双边?