Confidence level
The confidence level is statement that the “correct” answer lies within a given range of values, with a certain level of confidence. For example, “Based on our survey, we are 95% sure the average program participant is 20-30 years old.” In this case, 95% is the confidence level – it means there is a 95% chance that the right answer is between 20 and 30.
If we want to give a more precise answer, we are usually less certain it is right. For example, we might be only 60% sure the right answer is between 23 and 24 years old. On the other end of the spectrum, can be 100% certain the right answer is somewhere between 0 and 110 years old (because there’s no way the average age of the group is lower than 0 or higher than 110). This answer is definitely correct, but it’s not useful information!
When doing statistics like this, there is a trade-off between how sure we are of our answer (the confidence level), and how exact our answer is (the confidence interval).
See also: confidence interval