What does it mean when a researcher says a result is statistically significant?
In the context of our everyday lives a significant event usually means something important or noteworthy. In statistical terms, however, significance means something more specific! Statistical significance is a measure of how confident we are that an outcome is caused by the specific thing under investigation. Recall the example of our investigation into whether mood is improved by eating chocolate. Lets say that after doing some statistical analysis, we find that the chocolate with a high sugar content significantly improved mood compared to the no-sugar or low-sugar bar, which had no effect. What we mean is that we can be confident that the difference between the high-sugar bar and the other two types of chocolate is real. A second important point is that statistical significance does not always translate to practical or clinical significance. If we were to compare the speed of a person walking 100 meters compared to the speed of a person driving 100 meters and we did a statistical t
