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P-value being defined as the probability of observing a result equally or more extreme under a model H0. So if you start with with assumption that H0 is true, t
by vmuhonen 10y ago
P-value being defined as the probability of observing a result equally or more extreme under a model H0. So if you start with with assumption that H0 is true, there's not much you can say about alternative hypotheses.
The American Statistical Association actually put out a statement this year on the issue of p-value. You can find the whole article here http://dx.doi.org/10.1080/00031305.2016.1154108 http://dx.doi.org/10.1080/00031305.2016.1154108 but here are the main points:
1) P-values can indicate how incompatible the data are with a specified statistical model.
2) P-values do not measure the probability that the studied hypothesis is true, or the probability that the data were produced by random chance alone.
3) Scientific conclusions and business or policy decisions should not be based only on whether a p-value passes a specific threshold.
4) Proper inference requires full reporting and transparency.
5) A p-value, or statistical significance, does not measure the size of an effect or the importance of a result.
6) By itself, a p-value does not provide a good measure of evidence regarding a model or hypothesis.
As an additional curiosity, the group of writers was not completely unconflicted coming up those definitions and the article contains a number of supplemental articles by the individual authors to clarify/dispute some of the points made.
[edit] fixed formatting
- bayeslives 10y agoGood points. The NHST thing was invented by Neyman & Pearson as a tool for decision making, not for finding the truth.95% confidence means your intervals will be not to far off, in 95% of all samples. Perhaps this is nice fur Quality Asurance in factories. Where I do repeated measurements and where I want a simple YES or NO. But science usually asks: "what can I learn from this specific data? I don't do 100 samples and I'm not interested in being "not to far off moist of the time". I want a best estimation based on this specific sample". NHST does not give that answer. Bayes does.
- jsprogrammer 10y agoScience only asks, "Have I observed something contrary to my theories?" For non-deductive theories, the only real approach is to count the number of times you observed something agreeing with your theories vs. the total number of times you observed something (ie. p-value).