问题
单项选择题
Which of the following statements regarding confidence intervals is TRUE（）
A. The higher the alpha level, the wider the confidence interval.
B. The relationship between the alpha level and the confidence interval cannot be ascertained.
C. The lower the alpha level, the wider the confidence interval.
答案
参考答案：C
解析：
A higher degree of confidence requires a wider confidence interval. The degree of confidence is equal to one minus the alpha level, and so the wider the confidence interval, the higher the degree of confidence and the lower the alpha level. Note that the lower alpha level requires a higher reliability factor which results in the wider confidence interval.