NO.PZ2018062016000115
问题如下:
If analyst want to decrease the width of the confidence interval, which of the following statement should be selected.
选项:
A. increase sample variance
B. increase number of observations
C. increase confidence level
解释:
B is correct, if number of observation become larger, sample variance is smaller, the width of confidence interval become smaller.
观察的次数越多,样本方差越小,置信区间的宽度越小。
置信水平增加,critical value变大,置信区间变小