问题如下：
An analyst stated that, all else equal, increasing sample size will decrease both the standard error and the width of the confidence interval. The analyst’s statement is correct in regard to:
选项：
A. both the standard error and the confidence interval.
B. the standard error, but incorrect in regard to the confidence interval.
C. the confidence interval, but incorrect in regard to the standard error.
解释：
A is correct.
All else equal, a larger sample size will decrease both the standard error and the width of the confidence interval. In other words, the precision of the estimate of the population parameter is increased.
老师，这里不是应该随着N的增加，图形更倾向于正态分布（z分布）吗？标准误应该更倾向于总体标准差啊想那应该是变大啊。一个是总体标准差/根号下n（肯定大于1），一个是总体标准差。