explain xkcd - User contributions [en]

2144: Adjusting a Chair

2019-05-03T18:21:59Z

172.68.78.64: /* Explanation */

{{comic
| number = 2144
| date = May 1, 2019
| title = Adjusting a Chair
| image = adjusting_a_chair.png
| titletext = When I was looking at the box, I should have thought more about what "360 degrees of freedom" meant.
}}

==Explanation==
{{incomplete|Created by an EDITOR WITH TOO MANY DEGREES OF FREEDOM. Needs review. Do NOT delete this tag too soon.}}
This comic shows [[Cueball]]'s attempts to adjust a swivelling chair. This comically culminates in a massive chair with a big central seat and several other chairs branching off of it as Cueball continues learning how to to adjust it. The chair also apparently has so many controls it takes two hours to discover them all (although Cueball may have shown off his newly-discovered abilities in the mean time, so it might not take two hours of continuous experimentation).

As many people have experienced, these chairs can be quite difficult to raise, lower, or manoeuvre if one does not know how. Typically the chairs have multiple knobs and levers underneath the seat, which requires the user to rely on muscle memory to find them, since these levers are usually used while using the chair. One typically needs to experiment with the levers and knobs in a new chair to understand how to work the chair, and it appears Cueball is experimenting with them.

Each step gets farther away from what real-life office chairs could do. In sequence, Cueball finds his chair doing more and more surprising things:

{| class="wikitable"
! Step|| Sound || Chair's Ability
|-
| 1 || Clunk || Being able to recline the seat back. Many chairs do have this ability, which one can use for sitting comfort or perhaps to take a nap.
|-
| 2 || Hiss || Being able to raise or lower the seat. Most chairs have this ability, but the comic departs from real chairs in two ways. First, it's much higher than any real chair. Second, he can raise the height while sitting on it; under normal design, pressing the raise/lower lever while sitting on the chair is how one ''lowers'' the seat, using one's own weight to depress the spring or hydraulic piston (which is what's used here, as indicated by the sound). However, it's not uncommon to find a chair that has worn out or been improperly calibrated, so that it does rise even when sat on (especially with lighter people), or does not lower even when not sat upon with the lever active.
|-
| 3 || Poof || Being able to have the seat inflate. Although this could be useful (e.g. to help people who need to use extra seat cushions because of hemorrhoids or coccyx injury), it is not a typical office chair capability. However, in addition to simply inflating, Cueball's chair appears to actually make the seat longer and wider. This doesn't seem to have a lot of useful application in office chairs.
|-
| 4 || Unknown || Putting out branches and growing extra seats, wheels and backs. Chairs definitely cannot do this in real life{{Citation needed}} and use cases are doubtful.
|}

The title text refers to a common claim on such chairs, that the chair offers 360 degrees rotation and several degrees of freedom. This is a double entendre depending on if "360 degrees" or "degrees of freedom" is interpreted as an object. However, here it means there are 360 {{w|Degrees of freedom (mechanics)|mechanical degrees of freedom}}, which is the number of independent parameters that define the configuration of an object; in other words, the chair has 360 different levers and options, far more than a standard chair{{Citation needed}}.

==Transcript==
:[Cueball is shown adjusting a chair by pressing a button on the bottom of the chair. There is a caption in a frame over the top of the panel:]
:Adjusting a chair:

:[The seat back of the chair swings backward with him rather fast as shown by a few movement lines.]
:Chair: ''Clunk''

:[Cueball leans forward against the new chair position and presses another button.]

:[The chair extends to several times its previous height, very fast as shown by many lines beneath the seat.]
:Chair: ''Hiss''

:[At the top of this very high seat Cueball leans forward and presses another button.]

:[The seat expands in all directions, so Cueball only sits in the middle of it with his legs on top of the inflated cushion.]
:Chair: ''Poof''

:[The chair is now a massive contraption. It has 5 bases, each with wheels as the original chair. The main's seat is in the middle of the contraption with a single trunk going up from the five bases connecting them and the large cushion of the seat. Two entire chairs are branching out from underneath this central seat, they are each hanging in a thin wire more or less upside down to each side of the main trunk. Two poles are coming up from the central seat, each with a new seat and two back-to-back seat backs. Yet another seat is supported by a thin rod connecting the two top seats, looking almost like a table between the two chairs. Cueball is still on the main seat's cushion. He is holding on to one of the poles above him as he leans down and attempts to press yet another button beneath the seat. There is a caption in a frame over the top of the panel:]
:Two hours later...

{{comic discussion}}

[[Category:Comics featuring Cueball]]

Talk:432: Journal 4

2019-04-22T18:44:51Z

172.68.78.64: Some people argue that pacemaker jokes aren't funny but this is more of a metaphorical aspect being literal.

Black hat is going *really* out of character here. Lovesickness in this callous troll? Blasphemy! [[User:Davidy22|Davidy22]] ([[User talk:Davidy22|talk]]) 03:34, 30 October 2012 (UTC)
:We all have our moments. [[User:Thokling|Thokling]] ([[User talk:Thokling|talk]]) 15:06, 22 September 2013 (UTC)
::He does have a heart, he simply does not use it much. -- [[Special:Contributions/108.162.210.111|108.162.210.111]] 22:47, 4 April 2014 (UTC)
:::Well, a pacemaker, and it breaks down often, and it...okay I see your point. [[Special:Contributions/172.68.78.64|172.68.78.64]] 18:44, 22 April 2019 (UTC)

1574: Trouble for Science

2019-03-17T22:34:41Z

172.68.78.64: Diked out random statement.

{{comic
| number = 1574
| date = September 7, 2015
| title = Trouble for Science
| image = trouble_for_science.png
| titletext = Careful mathematical analysis demonstrates small-scale irregularities in Gaussian distribution
}}

==Explanation==
The comic highlights the fact that several well-publicized scientific critiques have recently been published that raise questions about some commonly accepted scientific methods. For scientists, these critiques serve as reminders of the dangers of overconfidence in any method, hopefully leading those who have naively accepted results to remember that any scientific conclusion is by its very nature tentative and limited by methodological reliability. However, popular press reporting of these papers may lead a general public of modest scientific literacy to the impression that science might be in trouble, as implied by the title. Some of these methodological issues and shortcomings are well known in the scientific community but are – for better or worse – the best toolkit science has at its disposal today. This is however greatly exaggerated by the last (fictional) headline, which suggests that Bunsen burners in fact have a cooling effect, which is of course absolutely ridiculous, but would nevertheless change one more fundamental scientific belief drastically. Additionally, each headline contains irony or a double meaning for comical effect.

The title of five scientific articles are shown:

;Many commercial antibody-based immunoassays are unreliable
This sentence is true. See Kebaneilwe Lebani, [http://espace.library.uq.edu.au/view/UQ:352531 Antibody Discovery for Development of a Serotyping Dengue Virus NS1 Capture Assay], 2014. In this PhD thesis, 11 references are given.

;Problems with the p-value as an indicator of significance
In empirical research, one is usually interested in effects / results / relationships in a population. However, for practical reasons, only smaller subsets of populations are available to the researcher. These are called samples. Usually an effect of interest is tested using a sample. The purpose of hypothesis testing is to determine whether the observed effect (or lack of effect) in a sample is a random artifact of our particular sample, or whether there is a good chance that it also exists in the population.

Generally a null hypothesis states that there is no effect in the population while the alternative hypothesis states that there is an effect.

P-values are used in hypothesis testing. The p-value is the probability of observing an effect / result / relationship in your sample data, given that no such effect / result / relationship exists in the population. It is based on the sample data and the particular statistic (such as sample average, t, or F). A statistic is the result of a calculation based on the sample. A p-value can be calculated for each statistic of interest. Formally, the p-value is the probability of observing a test statistic equal to or greater than the one based on the sample data, given that the null hypothesis is true.

The threshold for p-value cutoff, α, is pre-specified (usually 5% or 1%, which is more conservative). When the p-value is lower to or equal to α, the null hypothesis is rejected in favor of the alternative hypothesis. When it is higher than α, the null hypothesis is retained.

The value used for ''α'' has been proposed by [http://web.lru.dk/sites/lru.dk/files/lru/docs/kap9/kapitel_9_126_On_the_origins.pdf Fisher] and is arbitrary.

The use of p-values as a measure of statistical significance is frequently criticized, for example in [http://wiki.bio.dtu.dk/~agpe/papers/pval_notuseful.pdf Hubbard and Lindsay]. Randall has demonstrated this problem in the past in [[882: Significant]].
;Overfeeding of laboratory rodents compromises animal models

[http://tpx.sagepub.com/content/24/6/757.full.pdf Keenan et al.] makes this case. Additionally, the word model takes on two meanings. In one sense, a model can refer to a scientific description that makes sense of a phenomenon; in another sense, model can refer to an individual whose job it is to demonstrate fashions, typically fashionable outfits. Fashion models are notorious for being exceptionally thin, and so overfeeding would compromise their job as a model.

;Replication study fails to reproduce many published results
A [https://explorable.com/replication-study Replication Study] is a study designed to duplicate the results of a previous study by using the same methods for a different set of subjects and experimenters. It aims to recreate the results to gain confidence in the results of the previous study as well as ensuring that the findings of the previous study are transferable to other similar areas of study.

Randall is probably referring to this recent study described in Nature: [http://www.nature.com/news/over-half-of-psychology-studies-fail-reproducibility-test-1.18248 Over half of psychology studies fail reproducibility test.] It might also be a reference to at least 3 studies mentioned here: http://www.jove.com/blog/2012/05/03/studies-show-only-10-of-published-science-articles-are-reproducible-what-is-happening. There is also irony in the phrasing of the title because in biology replication is a form of reproduction.

Another possible interpretation of this headline is that a replication study, which may have successfully replicated the results of the specific study it was designed for, failed to reproduce the published results of many other unrelated studies. The headline is quite vague as to which results have been considered in this study.

;Controlled trials show Bunsen burners make things colder
The theme of this comic is that commonly accepted scientific methods can be unreliable, and the joke here is that a Bunsen burner, a device intended to heat things, is newly discovered to always cool things instead, which would be absurd.

In theory, yes, putting a Bunsen Burner underneath an object that's already incredibly hot would, slowly, equalize the temperature between the flame and object resulting in cooling. Given that a Bunsen Burner burns between 1000 K and 2000 K, there is probably some methodological error if the testing materials were already much hotter than the flame (more than 2000 Kelvin). It's also possible that if the "controlled trial" involved a Bunsen burner that was not lit, but was turned on to allow gas to flow, it would have a cooling effect as the gas expanded from the line pressure to atmospheric pressure. Another alternative theory is that a cold substance, such as cold water or frigid air, was fed through the burner against a warmer object.

Alternatively, a trial could be set up to test something against a Bunsen burner on the one hand, and an even hotter flame on the other hand. As compared to that hotter flame, the Bunsen burner would not heat up the tested material as much, resulting in something being made "colder" than the alternative.

As in the previous headline, the key to understanding the joke here is to examine the headline's ambiguity, as no clue is given about ''how'' the trials were controlled.

;Careful mathematical analysis demonstrates small-scale irregularities in Gaussian distribution
This is another joke of a premise that is obviously untrue. The {{w|Gaussian function|Gaussian distribution}} is a mathematical construct that is generally known as the bell curve or the Normal distribution. As it is an ideal mathematical construction, by definition, it cannot have any irregularities - similar to how the equation y = 2x + 1 cannot have small-scale irregularities. The joke probably alludes to the fact that many types of observations are frequently initially modeled as a Gaussian distribution, though on careful observation the actual distribution of outcomes will often deviate from a pure Gaussian distribution.

In addition, an experiment to test a Gaussian distribution will have a finite sample size, giving a non-exact Gaussian distribution. A possible paper submitted would conclude that this result is "approximately a normal distribution" with "small-scale irregularities". A news reporter without knowledge of statistics could easily misinterpret that this paper decisively concludes errors in the mathematical definitions (rather than coming from random error inherent in experimenting).

==Transcript==
:[Five panels, each with the top part of a scientific article, where only the title is legible. Below is the list of authors and subheading and text in unreadable wiggles.]

:Many Commercial Antibody-Based Immunoassays Are Unreliable

:Problems With the p-Value as an Indicator of Significance

:Overfeeding of Laboratory Rodents Compromises Animal Models

:Replication Study Fails to Reproduce Many Published Results

:Controlled Trials Show Bunsen Burners Make Things Colder

{{comic discussion}}
[[Category:Science]]
[[Category:Biology]]
[[Category:Chemistry]]
[[Category:Math]]
[[Category:Physics]]
[[Category:Statistics]]

875: 2009 Called

2016-12-26T22:07:16Z

172.68.78.64: /* Explanation */

{{comic
| number = 875
| date = March 21, 2011
| title = 2009 Called
| image = 2009 called.png
| titletext = 2017 called, but I couldn't understand what they were saying over all the screams.
}}

==Explanation==
The comic deconstructs a {{w|snowclone}} or common idiom - "X called, they want their Y back." Usually, X is a year (like 2009 here), and Y is something very popular in that year that is seen as ridiculous in the present day.

Here, [[Megan]] notices a Three-Wolf Moon T-shirt that [[Cueball]] apparently owns. The {{w|Three Wolf Moon|Three-Wolf Moon}} is a shirt of three wolves howling at the moon that reached meme status when several people posted ironic reviews giving it supernatural powers on {{w|Amazon}} around late 2008.

Megan says the snowclone, but before she can finish, Cueball pretends to take it literally (that is, that the year 2009 actually called her) and admonishes her for not telling them about {{w|2010 Haiti earthquake|the February 2010 earthquake in Haiti}} and {{w|2011 Tōhoku earthquake and tsunami|the March 2011 earthquake and tsunami in Japan}}. The comic was posted shortly after the latter, so it is reasonable to assume that it was created as a response to the disaster. Knowing Cueball, he's either preempting Megan's attempt to humiliate him and giving her a pretty good burn, or Cueball, being Cueball, actually thinks the past called.

The title text continues the snowclone, implying the end of humanity and/or the world will come about in 2017. However it is worth mentioning {{w|Donald J. Trump}} became {{w|President of the United States}} in 2017.

==Transcript==
:[Cueball is at computer. Megan is standing behind him, looking at clothes on the floor.]
:Megan: Is this a three wolf moon shirt?
:Megan: Dude, 2009 called, and they-
:Cueball: ''OH MY GOD!''
:Cueball: ''DID YOU WARN THEM?''
:Cueball: ''ABOUT HAITI AND JAPAN?''
:Megan: What? No, I-
:Cueball: You ''ASSHOLE!''

==See also==
*[[102: Back to the Future]]
*[[1072: Seventies]]

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

875: 2009 Called

2016-12-26T22:06:17Z

172.68.78.64: /* Explanation */

{{comic
| number = 875
| date = March 21, 2011
| title = 2009 Called
| image = 2009 called.png
| titletext = 2017 called, but I couldn't understand what they were saying over all the screams.
}}

==Explanation==
The comic deconstructs a {{w|snowclone}} or common idiom - "X called, they want their Y back." Usually, X is a year (like 2009 here), and Y is something very popular in that year that is seen as ridiculous in the present day.

Here, [[Megan]] notices a Three-Wolf Moon T-shirt that [[Cueball]] apparently owns. The {{w|Three Wolf Moon|Three-Wolf Moon}} is a shirt of three wolves howling at the moon that reached meme status when several people posted ironic reviews giving it supernatural powers on {{w|Amazon}} around late 2008.

Megan says the snowclone, but before she can finish, Cueball pretends to take it literally (that is, that the year 2009 actually called her) and admonishes her for not telling them about {{w|2010 Haiti earthquake|the February 2010 earthquake in Haiti}} and {{w|2011 Tōhoku earthquake and tsunami|the March 2011 earthquake and tsunami in Japan}}. The comic was posted shortly after the latter, so it is reasonable to assume that it was created as a response to the disaster. Knowing Cueball, he's either preempting Megan's attempt to humiliate him and giving her a pretty good burn, or Cueball, being Cueball, actually thinks the past called.

The title text continues the snowclone, implying the end of humanity and/or the world will come about in 2017. However it is worth mentioning {{w|Donald J. Trump}} became president of the united states in 2017.

==Transcript==
:[Cueball is at computer. Megan is standing behind him, looking at clothes on the floor.]
:Megan: Is this a three wolf moon shirt?
:Megan: Dude, 2009 called, and they-
:Cueball: ''OH MY GOD!''
:Cueball: ''DID YOU WARN THEM?''
:Cueball: ''ABOUT HAITI AND JAPAN?''
:Megan: What? No, I-
:Cueball: You ''ASSHOLE!''

==See also==
*[[102: Back to the Future]]
*[[1072: Seventies]]

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

1774: Adjective Foods

2016-12-19T15:36:00Z

172.68.78.64: /* Explanation */

{{comic
| number = 1774
| date = December 19, 2016
| title = Adjective Foods
| image = adjective_foods.png
| titletext = Contains 100% of your recommended daily allowance!
}}

==Explanation==
{{incomplete|First draft}}
This comic shows one of [[Randall]]'s goals in life- creating foods with 'adjective-only' names, where rather than Glazed Donuts or Lite Beer, just Glazed and Lite.

The title text furthers this with 'recommended daily allowance of XXX' and removing 'of XXX', making it vague enough to be meaningless.

==Transcript==
[An arrangement of packaged foodstuffs, labeled from left to right and top to bottom:]

* Premium Stone-ground '''Bespoke''', Cage-free
* Gourmet Fire-roasted '''Glazed''' Flambé
* Organic All-natural Locally-sourced '''Artisenal''', Kosher, Grade A
* Craft Barrel-aged Smoked '''Authentic Homemade''' Sun-dried Whole Extra Sharp
* Low-calorie '''Lite''' Original Flavor

I'm trying to trick supermarkets into carrying my new line of adjective-only foods.

{{incomplete transcript}}

{{comic discussion}}

1774: Adjective Foods

2016-12-19T15:34:42Z

172.68.78.64: /* Transcript */

{{comic
| number = 1774
| date = December 19, 2016
| title = Adjective Foods
| image = adjective_foods.png
| titletext = Contains 100% of your recommended daily allowance!
}}

==Explanation==
{{incomplete|First draft}}
This comic shows one of [[Randall]]'s goals in life- creating foods with 'adjective-only' names, where rather than Glazed Donuts or Lite Beer, just Glazed and Lite.

The title text furthers this with 'recommended daily allowance of XXX' and removing 'of XXX'.

==Transcript==
[An arrangement of packaged foodstuffs, labeled from left to right and top to bottom:]

* Premium Stone-ground '''Bespoke''', Cage-free
* Gourmet Fire-roasted '''Glazed''' Flambé
* Organic All-natural Locally-sourced '''Artisenal''', Kosher, Grade A
* Craft Barrel-aged Smoked '''Authentic Homemade''' Sun-dried Whole Extra Sharp
* Low-calorie '''Lite''' Original Flavor

I'm trying to trick supermarkets into carrying my new line of adjective-only foods.

{{incomplete transcript}}

{{comic discussion}}