Most statisticians use one of two levels: .95 (95%) or .99 (99%) Although any level can be used.
If .95 is selected, it means that if our study shows a 95% probability of truly representing the population, then we can safely assume (with 95% confidence) that our results are valid.
Or if we are comparing two groups, we can safely say the the differences between the two groups that was found in the sample are accurate 95% of the time.
Valid results are often referred to in publications as significant results or significant findings.
Confidence Intervals represent the range of scores that fall within our probability (.95 or .99). IOW: There is a 95% chance that the true mean of the population falls within our lower confidence level and our upper confidence level.