Statistically significant refers to something that is thought to have

sufficient evidence not to have occured by

chance. This is to say, we assume something to be statistically significant if the

likelihood of it having occured by chance is very low, hence the likelihood of occuring by

design is very high.

Usually, the critical value for statistical significance is p=<.05. This means that if we believe the probability of something having occured by chance is less than or equal to .05, we assume it has not occured by chance.

This critical value is not hard and fast, however. Depending on the issue being analyzed, the probability value may be .10, or lower, say .01, or .001.