NO.PZ2017092702000111
问题如下：
For a two-sided confidence interval, an increase in the degree of confidence will result in:
选项：
A.a wider confidence interval.
B.a narrower confidence interval.
C.no change in the width of the confidence interval.
解释：
A is correct.
As the degree of confidence increases (e.g., from 95% to 99%), a given confidence interval will become wider. A confidence interval is a range for which one can assert with a given probability 1 – α, called the degree of confidence, that it will contain the parameter it is intended to estimate.
随着置信度的增加（例如，从 95% 到 99%），给定的置信区间将变得更宽。 置信区间是一个范围，人们可以以给定的概率 1 – α（称为置信度）并代表它会包含我们要估计的参数。
我理解的两个概念：
confidence interval：μ±δ
confidence level/degree：置信度，为68%、90%……etc.
所以这道题我选了B，求解答
