Question

What does the confidence interval tell us about a samples mean?

Answer 1

Confidence intervals measure the degree of uncertainty or certainty in a sampling method. It can take any number of probabilities, with the most common being a 95% or 99% confidence level. In statistics it refers to the probability that a population parameter will fall between two set of values for a certain proportion of times. h

When we compute a confidence interval on the mean, we compute the mean of a sample in order to estimate the mean of the population. Clearly, if we already knew the population mean, there would be no need for a confidence interval.

A 95% confidence interval is a range of values that you can be 95% certain contains the true mean of the population. This is not the same as a range that contains 95% of the values.