More on P-Values

To any confused readers out there: The p-value is the probability of seeing something as extreme as the data or more so, if the null hypothesis were true. In social science (and I think in psychology as well), the null hypothesis is almost certainly false, false, false, and you don’t need a p-value to tell you this. The p-value tells you the extent to which a certain aspect of your data are consistent with the null hypothesis. A lack of rejection doesn’t tell you that the null hypothesis is likely true; rather, it tells you that you don’t have enough data to reject the null hypothesis. For more on this, see for example this paper with David Weakliem which was written for a nontechnical audience (link to pdf).

via Statistical Modeling, Causal Inference, and Social Science.