Question

What is meant by the α% confidence interval of the mean?

Answer 1

An alpha confidence interval for the mean is an interval (a, b) such that the mean of the population, µ, is inside it (i.e. a < µ < b) with (alpha) "confidence."
The endpoints of the interval, a and b, take values that depend on the random sample selected .........the confidence interval also depends on the random sample selected.