Definitions for "P value"
The P value gives the probability that the null hypothesis is correct.
The P value is a quantitative estimate of the probability that the observed difference between two groups could have happened by chance alone.
In statistics, a value very close to the probability of making a Type I error, the error of rejecting a true null hypothesis. A null hypothesis means no statistical significance, with any differences in populations or samples being due to chance. To make a Type I error is to find statistical significanc e when it is not there, as in mistaking chance results for treatment effects. For findings to be statistically significant, the probability of making a Type I error must be small, the smaller the better. The traditional cutoff value is 5 percent. If a p value is 5 percent or less (p=0.05), the null hypothesis can be rejected and there is statistical significance.