Significance

The results from an experiment are typically described in terms of significance.
The significance expressed as a precise numerical value indicates the probability that the scores really are from two different populations
This probability is also known as the level of confidence.
The lowest level of confidence which is accepted by scientists is 5% also expressed as the 0.05 level of probability.

There are three levels which are typically used and they are:
0.05 (5%)
0.01 (1%)
0.001 (.1%)

Confidence Interval