.95 or .99
- 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.