Answer:


Step-by-step explanation:
Notation
is the sample mean
indicates the population mean (the variable of interest)
s signifies the sample standard deviation
n denotes the sample size
Solution to the problem
The mean's confidence interval is derived from the following formula:
(1)
In this instance, the 9% confidence interval corresponds to:

We can determine the mean using the following:

Additionally, the margin of error can be calculated as:

The margin of error for this situation is expressed as:

Next, we find the standard error:

The critical value for a 95% confidence interval using a normal standard distribution is roughly 1.96, and substituting gives us:

For the 98% confidence interval, the significance corresponds to
and
with a critical value of 2.326, yielding a confidence interval of:

