explain xkcd - User contributions [en]

Talk:524: Party

2015-03-22T09:06:47Z

GeniusBooks: Are the last three frames a reference to CSI: Miami?

''Yo, dawg, I heard you like to be rickrolled, so I rolled Rick into a rickroll so you could be Rick rickrolled rolled!'' [[User:Thokling|Thokling]] ([[User talk:Thokling|talk]]) 09:27, 25 September 2013 (UTC)

Is it me, or is having Astley put on a pair of sunglasses to deliver a dry punchline reminiscent of CSI: Miami, where Horatio Caine gets in a clever one-liner at the end of the opening tag, almost always while donning sunglasses? [[User:GeniusBooks|GeniusBooks]] ([[User talk:GeniusBooks|talk]])

552: Correlation

2015-03-22T08:58:31Z

GeniusBooks: /* Explanation */ Addition of a note explaining the title text's reference to Ferris Bueller's Day Off.

{{comic
| number = 552
| date = March 6, 2009
| title = Correlation
| image = Correlation.png
| titletext = Correlation doesn't imply causation, but it does waggle its eyebrows suggestively and gesture furtively while mouthing 'look over there'.
}}

==Explanation==
This comic focuses on the apparent difficulty people have in understanding the difference between {{w|Correlation and dependence|correlation}} and {{w|Causality|causation}}. When two variables (like blood cholesterol levels and heart disease) are positively correlated, it means that as one variable increases so does the other, whereas a negative correlation means that as one variable increases, the other decreases. The human brain is very good at seeing patterns and deducing rules, and the seemingly natural conclusion is that that the one is leading to the other. In the example, that high blood cholesterol causes heart disease.

This may well be true. The positive correlation is certainly not an argument '''against''' such a conclusion. But it is only one type of evidence, and is certainly not proof.

The relationship between diet and blood chemistry and heart disease is a complex one, but simpler examples abound. For example, if you tallied the sales of sunglasses and incidence of skin cancer by region, you would probably find that there is a high positive correlation. That is, in locations where many people buy sunglasses, there are also many cases of skin cancer. Here it would seem silly to believe that wearing sunglasses can cause skin cancer, but this is exactly the same thinking that allowed us to conclude that blood cholesterol causes heart disease. Correlations do have the ability to mislead us. In this example, both sunglasses and skin cancer are directly affected by a third factor (specifically, a climate where many people expose themselves to the sun).

In essence, when two variables are correlated it does not provide evidence that one variable has caused the other. All it says is that their trends move in relation to each other. The correlation could be due to causality, but it could equally be due to other factors, or it could even be a random result.

In this situation [[Cueball]] is explaining to Megan his realization that correlation is not the same thing as causation. He further explains that his belief changed after taking a statistics class. [[Megan]], then makes the seemingly obvious leap and declares that his realization was the result of taking the statistics course. Cueball's final response of "Well, Maybe." is a joke on Megan's behalf. Of course Cueball would know whether his new knowledge is caused by the course, but he points out that Megan can't be certain about the causation.

The title text plays on two meanings of the word ''imply'': have as consequence, or insinuate. In the statement {{w|correlation does not imply causation}}, ''correlation'' is here seen as a person, giving you subtle hints where to look for the cause. This is a metaphor for research, where the correlation must be investigated further, perhaps in a wider scope or with the consideration of more variables, so that the reason for it is understood. For example, {{w|Barry Marshall}} and {{w|Robin Warren}} noticed that the presence of ''{{w|Helicobacter pylori}}'' was highly correlated with duodenal ulcer patients. They investigated further. Result: the Nobel Prize in Medicine.

In addition, the title text's reference to waggling eyebrows and gesturing furtively while mouthing "look over there" is clearly a reference to the movie Ferris Bueller's Day Off, in which the character of Cameron Frye tries to alert Ferris that Ferris's father is in the next cab over, and they are about to be discovered ditching school. What Randall is saying with this reference is that Correlation (if it were a character in a movie) is desperately trying to draw attention to Causation without openly stating this intention, and perhaps that correlation is a good place to start when looking for causation.

==Transcript==
:[Cueball is talking to Megan.]
:Cueball: I used to think correlation implied causation.

:Cueball: Then I took a statistics class. Now I don't.

:Megan: Sounds like the class helped.
:Cueball: Well, maybe.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Statistics]]

Talk:273: Electromagnetic Spectrum

2015-03-06T03:04:23Z

GeniusBooks: Clarification that microwave ovens don't resonate at the harmonic frequency of water, but use dialectric heating instead.

"Light particles were formerly carried by the aether, which was decommissioned in 1897 due to budget cuts." Ohh, this is so INCOMPLETE, just read the comic, I still laughing and I can't stop. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 18:20, 6 July 2013 (UTC)

Now why did Randall Munroe go with the old 1960s notion of putting gamma/cosmic rays at the high end of the spectrum. Back then certain events in detectors were thought to be caused by photons of higher frequency than gamma rays, but now those are known to instead be made by very energetic charged nuclei not electromagnetism. Thus "cosmic rays" not part of EM spectrum at all. --[[User:RalphSiegler|RalphSiegler]] ([[User talk:RalphSiegler|talk]]) 15:07, 7 July 2013 (UTC)

;Any help here is welcome!

...but please discuss major changes here before. The page is still marked as incomplete, I am happy about any new ideas.--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 21:42, 15 July 2013 (UTC)
:Going forward, I'll assume {{w|WP:BOLD|Wikipedia's "Be bold" guideline}} applies to this wiki (although not part of the wikimedia project), too. Thus, I'll continue to make changes I consider uncontroversial without first discussing them, if I'm sufficiently confident in them, including major ones. In judging how controversial a potential change might be, I'll take the respective article's edit history and talk page into account. I try to write good edit summaries, so these should usually give you my reason or motivation for making the edit it question. If you revert them, please {{w|Wikipedia:Revert only when necessary#Explain_reverts|do tell why you disagree with the specific edit}} ({{w|Wikipedia:Don't revert due solely to "no consensus"|except that is hasn't previously been discussed}}) in the edit summary or on the talk page, so that a discussion can actually start. --[[User:Das-g|Das-g]] ([[User talk:Das-g|talk]]) 12:49, 6 August 2013 (UTC)

;Some suggestions
* The year 1897 might refer to {{w|Joseph Larmor}}'s publication about the later so-called {{w|Lorentz transformation}}.
* "The Wave" might also refer to the {{w|The Third Wave|experiment}}/{{w|The Wave (novel)|novel}}.
* The actual electromagnetic spectrum of toasters is (mostly) in the IR range.
* I'm pretty sure there is some kind of joke w.r.t censorship and the Patriot Act (afaik the Patriot Act is actually more the opposite of censoring, though i.e. making more information available—to intelligence agencies)
* I agree with [[User:Das-g]] that X-Ray glasses unlikely refer to {{w|full-body scanner}}s
--[[User:Chtz|Chtz]] ([[User talk:Chtz|talk]]) 00:23, 16 July 2013 (UTC)

;Mail-order X-Ray glasses
I doubt "mail-order X-Ray glasses" is a reference to full body scanners, for the following two reasons:
# {{w|Full body scanner}}s are heavy and bulky equipment. While —if you'd manage to order one— you can probably have it shipped to a destination of your choice, delivery will most likely not happen by mail, which would be the definition of a {{w|mail order}}.
# While it might be possible to connect certain {{w|Stereoscopy#Head-mounted_displays|VR goggles}} or similar glasses-like periphery to some full body scanners, they are usually operated with screens that do not resemble {{w|spectacles}}.

In my opinion, it's much more likely that a once popular {{w|X-Ray Specs (novelty)|a novelty item}} that could actually be ordered from catalogues/adverts and could sent by mail (because it was flat and light, consisting of cardboard and plastic foil) is being referenced. 
-- [[User:Das-g|Das-g]] ([[User talk:Das-g|talk]]) 21:34, 29 July 2013 (UTC)

:It's been a week and there have not been any replies, so if there still aren't any for another week (i.e. until 2013-08-13) I'll consider [http://www.explainxkcd.com/wiki/index.php?title=273:_Electromagnetic_Spectrum&diff=43862&oldid=43142 my first change] to this article undisputed and re-do it. However, I ''will not'' re-do my [http://www.explainxkcd.com/wiki/index.php?title=273:_Electromagnetic_Spectrum&diff=next&oldid=43862 second change] without explicitly putting it up for discussion here on the talk page, first, as I expect it to be a bit more controversial. (I'll put the second change up for discussion if/when I re-do the first change, as the second only makes sense if the first is acceptable, anyway.) --[[User:Das-g|Das-g]] ([[User talk:Das-g|talk]]) 12:08, 6 August 2013 (UTC)
::Because there still weren't any replies, I've [http://www.explainxkcd.com/wiki/index.php?title=273:_Electromagnetic_Spectrum&diff=46445&oldid=46412 redone my first change]. --[[User:Das-g|Das-g]] ([[User talk:Das-g|talk]]) 22:30, 13 August 2013 (UTC)

;X-ray glasses and your sister
Is the second sentence of the title text ("Also sometimes I try to picture your sister naked.") a reference to how X-Ray Specs were {{w|X-Ray Specs (novelty)#Novelty_value|sometimes advertized}}? 
--[[User:Das-g|Das-g]] ([[User talk:Das-g|talk]]) 22:30, 13 August 2013 (UTC)

"Gal" could refer to 1cm/s2, or a galileo. http://en.wikipedia.org/wiki/Gal_%28unit%29[[Special:Contributions/173.245.56.208|173.245.56.208]] 05:34, 12 January 2015 (UTC)

Regarding the reference to microwave ovens in the explanation, I would like to point out that comic 843:Misconceptions references the [[wikipedia:List_of_common_misconceptions|list of common misconceptions]], which in the Food and Cooking section clearly states that microwaves don't work at the frequency of water but instead uses [[wikipedia:Dialectric_heating|dialectric heating]] to cook food. Obviously that comic is later than this one, but it should be considered for the explanation above. Thanks! [[User:GeniusBooks|GeniusBooks]] ([[User talk:GeniusBooks|talk]])