Probability Statistics: Get an average and apply the average to each individual and see how much they deviate from the average.  Come to a standard deviation and plot the deviation on the bell-shaped curve.  95% of the people will be inside the deviations of the curve.  2.5% on each side outside the curve.  If outside two standard deviations, you vary from the average, not by chance.  You are statistically distinct from everyone else.  The probability is less than or equal to 5% of a particular result, that is statistically significant.  That intervention is statistically significant and scientifically valid.  The treatment that was rendered, if the standard deviation falls to 5% or less, then it is statistically significant.
(i)    A scientist wants to show the FDA that there is less than 5% that the treatment and results were due to chance.
(ii)    This is important b/c in voir dire, you want to see if your scientific expert is using junk science or valid statistics.