Question

where would you use a confidence interval in everyday life? When n increases what happens to the width of a confidence interval?

Answer 1

As the confidence level increases, the width of the confidence interval increases. They are directly proportional to each other.

Increasing the confidence level means we want to be more sure that the parameter for which interval is found actually lies within that interval. So the broader the interval the more will be the chances, hence increasing confidence level , increases the critical value, which increases the margin of error and hence the width of confidence interval.