NO.PZ2015120604000130
问题如下:
We want to use z-statistic to construct confidence interval for a normally distribution. Assume the sample size is 100, sample mean is 15% and the standard deviation of sample is 25%. The significance level is supposed to be 10% , the confidence interval is :
选项:
A.
- 10.88% to 19.13%.
B.
10.88% to 19.13%.
C.
10.88% to 20.57%.
解释:
B is correct.
In this case, we can know that the Confidence Interval=[Point Estimate +/- (reliability factor)*Standard error]=
老师,既然题目说是正态分布,而且是选择题。想问下能否利用正态分布的特性,代入选项解题?正太分布中轴是均值,题干给出的置信区间应该也是轴对称。
直接带入选项,分位点-均值:19.13-15=4.13
均值-分位点到均值的距离:15-4.13=10.87
然后选出最符合的的选项