How does probability relate to statistical significance?
Probability is a mathematical calculation. Significance is a relative measure of risk acceptance for a given difference in probable outcomes.
The probability of an event can be calculated with data from observations of previous events. Its accuracy is dependent on the quality and amount of data on which it is based.
Statistical significance is one way to evaluate whether variations in probability are due to specific causes or random occurrences. The level of statistical significance accepted for a particular result is also an arbitrary determination of the user's risk tolerance - how readily they will accept the risk of an incorrect conclusion.