Answer:

Explanation:
Given parameters
Z interval E = (23.305,25.075)
mean xbar = 23.69
number of samples n = 30
Required
we are to find the confidence interval for the Z interval given.
The formula for finding the confidence interval is expressed as shown below;
where;
xbar is the mean = 30
E is the margin of error

U = upper limit = 23.305
L = lower limit = 25.075

The confidence interval is therefore expressed as

Hence the confidence interval is expressed as
