Talk:P-value

Misleading examples

The examples given are rather misleading. For example in the section about the rolling of two dice the articles says. "In this case, a single roll provides a very weak basis (that is, insufficient data) to draw a meaningful conclusion about the dice. "

However it makes no attempt to explain why this is so - and a slight alteration of the conditions of the experiment renders this statement false.

Consider a hustler/gambler who has two sets of apparently identical dice - one of which is loaded and the other fair. If he forgets which is which - and then rolls one set and gets two sixes immediately then it is quite clear that he has identified the loaded set.

The example relies upon the underlying assumption that dice are almost always fair - and therefore it would take more than a single roll to convince you that they are not. However this assumption is never clarified - which might mislead people into supposing that a 0.05 p value would never be sufficient to establish statistical significance. Richard Cant — Preceding unsigned comment added by 152.71.70.77 (talk)

That cheating gambler would be wrong in his conclusion 1 out of 36 times though Yinwang888 (talk) 16:31, 24 November 2021 (UTC)

Recent edits

It is rather traditional that values of 5% and 1% are chosen as significance level. In fact the value of p itself is an indication of the strenght of the observed result. Whether or not the null hypothesis may be rejected is also a matter of 'taste'. But anyway does a small p-value suggest that the observed data is sufficiently inconsistent with the null hypothesis.Madyno (talk) 09:47, 8 December 2021 (UTC)

The .05 level is by far the most conventional level. The .01 level is sometimes used but much more rarely. But in any case, the "Usage" section was mainly just a repetition of what had already been said in the "Basics Concepts" section and the "Definition and Interpretation" section, so I've trimmed it down considerably. A section that's just restating what's already been said doesn't need to give so much detail (if it needs to exist at all). 23.242.195.76 (talk) 02:28, 15 December 2021 (UTC)

Does the hyphenization indeed vary?

"As far as I'm aware, APA guidelines say you have to italicize every statistic, period. Saying "p value" is no different than saying "DP value". I mean, it's not a symptom of dropping the hyphen, but merely a situation where the topic was the value of p, rather than the p-value. Whether that makes sense, i.e., that there really exists a difference between these situations which justifies the different styling, I do not know. But I'm under the impression that that's how people use it. It's the rationalization that I have been able to do, since I have seen many articles formatted under APA style that use "p-value" at some point. ~victorsouza (talk) 16:57, 17 March 2022 (UTC)