Answer:
b) The width of the confidence interval becomes narrower when the sample mean increases.
Step-by-step explanation:
The confidence interval can be calculated as:
a) The width of the confidence interval becomes wider as the confidence level increases.
The above statement is true as the confidence level increases the width increases as the absolute value of test statistic increases.
b) The width of the confidence interval becomes narrower when the sample mean increases.
The above statement is false. As the sample mean increases the width of the confidence interval increases.
c) The width of the confidence interval becomes narrower when the sample size n increases.
The above statement is true as the sample size increases the standard error decreases and the confidence interval become narrower.