Statistical Significance
Significance tests are performed to see if the
null hypothesis can be rejected. If the
null hypothesis is rejected, then the effect found in a
sample is said to be statistically
significant. If the null hypothesis is not rejected, then the effect
is not significant. The experimenter chooses a
significance level before conducting the
statistical analysis. The significance level chosen determines the
probability of a
Type I error. A
statistically significant effect is not necessarily practically
significant.