Editing Talk:1478: P-Values

IMHO the current explanation is misleading. The [http://en.wikipedia.org/wiki/P-value p-value] describes how well the experiment output fits hypothesis. The hypothesis can be that the experiment output is random.
The low p-values point out that the experiment output fits well with behavior predicted by the hypothesis. The higher the p-value the more the observed and predicted values differ.[[User:Jkotek|Jkotek]] ([[User talk:Jkotek|talk]]) 08:54, 26 January 2015 (UTC)
: High p-values do not signify that the results differ from what was predicted, they simply indicate that there are not enough results for a conclusion. --[[Special:Contributions/108.162.230.113|108.162.230.113]] 20:13, 26 January 2015 (UTC)

I read this comic as a bit of a jab at either scientists or media commentators who want the experiments to show a particular result. As the significance decreases, first they re-do the calculations either in the hope that result might have been erroneous and would be re-classified as significant, or intentionally fudge the numbers to increase the significance. The next step is to start clutching at straws, admitting that while the result isn't ''[[Technically]]'' significant, it is very close to being significant. After that, changing the language to 'suggestive' may convince the general public that the result is actually more significant than it is, while also changing the parameters of the 'significance' value allows it to be classified as significant. Finally, they give up on the overall results, and start pointing out small sections which may by chance show some interesting features.

All of these subversive efforts could come about because of scientists who want their experiment to match their hypothesis, journalists who need a story, researchers who have to justify further funding etc etc. --[[User:Pudder|Pudder]] ([[User talk:Pudder|talk]]) 09:01, 26 January 2015 (UTC)
:I like how you have two separate categories - "scientists" and "researchers" with each having two different goals :) [[User:Nyq|Nyq]] ([[User talk:Nyq|talk]]) 10:12, 26 January 2015 (UTC)
: As a reporter, I can assure you that journalists are not redoing calculations on studies. Journalists are notorious for their innumeracy; the average reporter can barely figure the tip on her dinner check. Most of us don't know p-values from pea soup.[[Special:Contributions/108.162.216.78|108.162.216.78]] 16:44, 26 January 2015 (UTC)

This one resembles [https://mchankins.wordpress.com/2013/04/21/still-not-significant-2/ this interesting blog post] very much.--[[Special:Contributions/141.101.96.222|141.101.96.222]] 13:26, 26 January 2015 (UTC)

[[File:null_hypothesis.png]]<br/>
[[User:Sten|'''S<small>TEN</small>''']] <small>([[User talk:Sten|talk]])</small> 13:33, 26 January 2015 (UTC)
:Heh.  [[Special:Contributions/173.245.56.189|173.245.56.189]] 20:06, 26 January 2015 (UTC)

See http://xkcd.com/882/ for using a subgroup to improve your p value. Sebastian --[[Special:Contributions/108.162.231.68|108.162.231.68]] 23:02, 26 January 2015 (UTC)
:I agree. The part about p >= 0.1 reminded me of that comic. [[User:S|S]] ([[User talk:S|talk]]) 01:25, 27 January 2015 (UTC)

This comic may be ridiculing the arbitrariness of the .05 significance cutoff and alluding to the "new statistics" being discussed in psychology.[http://www.psychologicalscience.org/index.php/publications/observer/2014/march-14/theres-life-beyond-05.html]<br>[[Special:Contributions/108.162.219.163|108.162.219.163]] 23:06, 26 January 2015 (UTC)

The "redo calculations" part could just mean "redo calculations with more significant figures" (i.e. to see whether this 0.050 value is actually 0.0498 or 0.0503). --[[Special:Contributions/141.101.104.52|141.101.104.52]] 13:36, 28 January 2015 (UTC)
:Agreed. I first understood it as someone thinking that 0.05 is a "too round" value, and some calculations tend to raise suspicions when these values pop up. [[Special:Contributions/188.114.99.189|188.114.99.189]] 21:28, 7 December 2015 (UTC)

;TL;DR
As someone who understands p values, IMO this explanation is ''way'' too technical. I really think the intro paragraph should have a short, simplified version that doesn't require any specialized vocabulary words except "p-value" itself. Then talk about controls, null hypothesis, etc, in later paragraphs. - [[User:Frankie|Frankie]] ([[User talk:Frankie|talk]]) 16:52, 28 January 2015 (UTC)
: That is [http://fivethirtyeight.com/features/not-even-scientists-can-easily-explain-p-values/ nearly impossible]. I'm using the American Statistical Association's [http://amstat.tandfonline.com/doi/full/10.1080/00031305.2016.1154108#_i27 definition] that "Informally, a p-value is the probability under a specified statistical model that a statistical summary of the data (e.g., the sample mean difference between two compared groups) would be equal to or more extreme than its observed value" until a better one comes. That said, the difficulty of explaining p-value is no excuse to use the wrong interpretation of "probability that observed result is due to chance".--[[User:Troy0|Troy0]] ([[User talk:Troy0|talk]]) 06:27, 24 July 2016 (UTC)

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There's an irony in the use of hair colour as a suspect subgroup analysis... hair colour can factor in to studies.  Ignoring the (probably wrong) common idea that red heads have a lower effectiveness rating for contraceptives, there do seem to be some suggestions that the recessive mutated gene does have implications beyond hair colour.  Getting sunburn easily is one we all know, but how about painkiller and aesthetic efficiency? For example: http://healthland.time.com/2010/12/10/why-surgeons-dread-red-heads/ --[[Special:Contributions/141.101.99.84|141.101.99.84]] 09:15, 18 June 2015 (UTC)