2048: "Curve-Fitting"

This forum is for the individual discussion thread that goes with each new comic.

Moderators: Moderators General, Prelates, Magistrates

User avatar
LucasBrown
Posts: 299
Joined: Thu Apr 15, 2010 2:57 am UTC
Location: Poway, CA

2048: "Curve-Fitting"

Postby LucasBrown » Wed Sep 19, 2018 6:21 pm UTC

Image
Title text: Cauchy-Lorentz: "Something alarmingly mathematical is happening, and you should probably pause to Google my name and check what field I originally worked in."

The text accompanying the piecewise plot is missing an ending quotation mark.

User avatar
Soupspoon
You have done something you shouldn't. Or are about to.
Posts: 3659
Joined: Thu Jan 28, 2016 7:00 pm UTC
Location: 53-1

Re: 2048: "Curve-Fitting"

Postby Soupspoon » Wed Sep 19, 2018 7:24 pm UTC

What Randall doesn't know is that actually those dots are all points on a Radar Plot. Something to do with responses to Rorschach tests, I think.

User avatar
Old Bruce
Posts: 165
Joined: Tue Jun 28, 2016 2:27 pm UTC

Re: 2048: "Curve-Fitting"

Postby Old Bruce » Wed Sep 19, 2018 8:00 pm UTC

Soupspoon wrote:What Randall doesn't know is that actually those dots are all points on a Radar Plot. Something to do with responses to Rorschach tests, I think.

... probable responses to Rorschach tests...

User avatar
Sableagle
Ormurinn's Alt
Posts: 1900
Joined: Sat Jun 13, 2015 4:26 pm UTC
Location: The wrong side of the mirror
Contact:

Re: 2048: "Curve-Fitting"

Postby Sableagle » Wed Sep 19, 2018 8:49 pm UTC

2048.png
Oh, Willie McBride, it was all done in vain.

SAI Peregrinus
Posts: 16
Joined: Mon Mar 30, 2015 8:02 pm UTC

Re: 2048: "Curve-Fitting"

Postby SAI Peregrinus » Wed Sep 19, 2018 8:51 pm UTC

Reminds me a bit of the "Datasaurus Dozen" graphs.

https://www.autodeskresearch.com/publications/samestats

kkt
Posts: 22
Joined: Fri Mar 20, 2009 10:37 pm UTC

Re: 2048: "Curve-Fitting"

Postby kkt » Wed Sep 19, 2018 9:44 pm UTC

Is there a trick to the hidden text punchline? Lorentz was in theoretical physics, especially electromagnetism. Cauchy was a civil engineer working on a canal for Napoleon. Neither seem especially disreputable.

User avatar
gmalivuk
GNU Terry Pratchett
Posts: 26528
Joined: Wed Feb 28, 2007 6:02 pm UTC
Location: Here and There
Contact:

Re: 2048: "Curve-Fitting"

Postby gmalivuk » Wed Sep 19, 2018 10:30 pm UTC

It's not a joke about the dudes, it's about their probability distribution, which is in many ways "pathological" as a distribution, though I don't know how often it's used to fit curves.
Unless stated otherwise, I do not care whether a statement, by itself, constitutes a persuasive political argument. I care whether it's true.
---
If this post has math that doesn't work for you, use TeX the World for Firefox or Chrome

(he/him/his)

Mjb
Posts: 24
Joined: Thu Jan 01, 2009 5:32 am UTC

Re: 2048: "Curve-Fitting"

Postby Mjb » Wed Sep 19, 2018 11:03 pm UTC

Ah, the eternal source of statistics jokes.

https://algotrading101.com/blog/1543426 ... timization
http://ucanalytics.com/blogs/machine-le ... ed-part-1/
https://xkcd.com/1347/
https://xkcd.com/1725/

An image search brings up plenty more opportunities for suspicious fitting - B-spline, devil's curve (if you can present your data in polar) - and the occasional guide on how to dress for one's body shape.

User avatar
Flumble
Yes Man
Posts: 2075
Joined: Sun Aug 05, 2012 9:35 pm UTC

Re: 2048: "Curve-Fitting"

Postby Flumble » Wed Sep 19, 2018 11:09 pm UTC

I'm loving Sableagle's interpretation of the datas. :lol:

The "house of cards" diagram reminds me of when I first learned about polynomial interpolation. Despite some occasional overshooting they result in nice smooth motion ...until you try and see what prediction power it has and *BLAM* everything explodes.

Graham Finch
Posts: 59
Joined: Tue Mar 11, 2008 9:25 am UTC

Re: 2048: "Curve-Fitting"

Postby Graham Finch » Thu Sep 20, 2018 6:27 am UTC

But what message do the polynominal people send?

wumpus
Posts: 533
Joined: Thu Feb 21, 2008 12:16 am UTC

Re: 2048: "Curve-Fitting"

Postby wumpus » Thu Sep 20, 2018 1:35 pm UTC

Graham Finch wrote:But what message do the polynominal people send?


I thought "House of Cards" was what you got with a polynomial curve fitting (or at least a sufficiently large polynomial for such a good fit).

User avatar
CorruptUser
Posts: 10238
Joined: Fri Nov 06, 2009 10:12 pm UTC

Re: 2048: "Curve-Fitting"

Postby CorruptUser » Thu Sep 20, 2018 9:36 pm UTC

This is why I just use a regression where appropriate, multivariate if there's sufficient data, and call it a day. Anything more is the mathematical equivalent of sophistry.

User avatar
Archgeek
Posts: 200
Joined: Wed May 02, 2007 6:00 am UTC
Location: Central US
Contact:

Re: 2048: "Curve-Fitting"

Postby Archgeek » Thu Sep 20, 2018 10:52 pm UTC

Mjb wrote:Ah, the eternal source of statistics jokes.

https://algotrading101.com/blog/1543426 ... timization
http://ucanalytics.com/blogs/machine-le ... ed-part-1/
https://xkcd.com/1347/
https://xkcd.com/1725/

An image search brings up plenty more opportunities for suspicious fitting - B-spline, devil's curve (if you can present your data in polar) - and the occasional guide on how to dress for one's body shape.

I love how the Teacher's T distribution kinda looks like Barad-dûr.
"That big tube down the side was officially called a "systems tunnel", which is aerospace contractor speak for "big tube down the side."

User avatar
ucim
Posts: 6563
Joined: Fri Sep 28, 2012 3:23 pm UTC
Location: The One True Thread

Re: 2048: "Curve-Fitting"

Postby ucim » Fri Sep 21, 2018 1:12 am UTC

The key to curve fitting is to ask the question "how necessary is the complication of this particular equation when I remove some data. That shows how robust the curve fit is. This can be taken to the limit of removing all the data; the resulting curve should be perfect.

Jose
Order of the Sillies, Honoris Causam - bestowed by charlie_grumbles on NP 859 * OTTscar winner: Wordsmith - bestowed by yappobiscuts and the OTT on NP 1832 * Ecclesiastical Calendar of the Order of the Holy Contradiction * Please help addams if you can. She needs all of us.

User avatar
cellocgw
Posts: 1947
Joined: Sat Jun 21, 2008 7:40 pm UTC

Re: 2048: "Curve-Fitting"

Postby cellocgw » Fri Sep 21, 2018 11:18 am UTC

Sableagle wrote:2048.png
..mmmpphhh guess you'll have to look back to see the image I tried to quote.

It could be (and often is, these days) a lot worse: just imagine what the results would be if you tried to apply machine-learning to distinguish among those groupings.

Also, as the local representative of The World Convocation of Carls, I resent the implication :P
https://app.box.com/witthoftresume
Former OTTer
Vote cellocgw for President 2020. #ScienceintheWhiteHouse http://cellocgw.wordpress.com
"The Planck length is 3.81779e-33 picas." -- keithl
" Earth weighs almost exactly π milliJupiters" -- what-if #146, note 7

User avatar
zjxs
Posts: 63
Joined: Tue Sep 29, 2009 6:04 am UTC
Location: The Cloud

Re: 2048: "Curve-Fitting"

Postby zjxs » Fri Sep 21, 2018 11:10 pm UTC

LucasBrown wrote:Comic strip and alt-text.


I have done all of these. But not to the same data.

User avatar
MarkGyver
Posts: 35
Joined: Sun Nov 09, 2008 6:56 am UTC

Re: 2048: "Curve-Fitting"

Postby MarkGyver » Tue Sep 25, 2018 3:07 pm UTC

Congrats on the big round-number milestone! Xkcd now needs 0xC bits to represent its comic numbers.
Generation 0: The first time you see this, copy it into your signature and change it so that it looks like you inspired this signature. Social experiment.

User avatar
phlip
Restorer of Worlds
Posts: 7556
Joined: Sat Sep 23, 2006 3:56 am UTC
Location: Australia
Contact:

Re: 2048: "Curve-Fitting"

Postby phlip » Thu Sep 27, 2018 12:46 am UTC

kkt wrote:
Is there a trick to the hidden text punchline? Lorentz was in theoretical physics, especially electromagnetism. Cauchy was a civil engineer working on a canal for Napoleon. Neither seem especially disreputable.

It's a bit of an ambiguous pronoun, but I think it's supposed to mean that you'd want to Google the credentials of whoever is using the Cauchy-Lorentz distribution in a statistical analysis, rather than Cauchy and Lorentz themselves. Because if you're trying to use that distribution in an actual applied setting, you're probably either doing something very clever, or very wrong.

My favourite one of these was a couple years back, where someone plotted tournament attendance figures for some game, slapped on a 6th-degree-polynomial regression line (probably because that's the highest Excel will go) and saw it started to go down slightly at the end (because, of course, the ends are the most stable part of a high-degree polynomial fit) and then took to Twitter/reddit to chicken little about how the game had peaked and attendance was falling and the game was being mismanaged and etc etc and soapbox about all their favourite gripes with how the game was being run...

Code: Select all

enum ಠ_ಠ {°□°╰=1, °Д°╰, ಠ益ಠ╰};
void ┻━┻︵​╰(ಠ_ಠ ⚠) {exit((int)⚠);}
[he/him/his]

teal4two
Posts: 1
Joined: Wed Sep 26, 2018 11:08 pm UTC

Re: 2048: "Curve-Fitting"

Postby teal4two » Fri Sep 28, 2018 12:56 am UTC

Post disapproved:

"2048: "Curve-Fitting""

Reason: The reported message has the only purpose to advertise for a website or another product. If you’re a bot, posting the last rejection is a giveaway. If you’re not a bot.... you kinda look like a bot right now..

Thu Sep 27, 2018 1:37 pm America/Los_Angeles
-----------------

????
I posted a link to a similar plot from the journal Science.
If this was handled by a human moderator, it should have been clear from the link that it was unlikely to be an ad. A human might actually have looked at the link and been able to make a rational decision.
So presumably this was addressed by AI, with only the A being appropriate.

PS I am not even that sure of what a bot is, much less spend my time studying their behavior.

User avatar
SecondTalon
SexyTalon
Posts: 26263
Joined: Sat May 05, 2007 2:10 pm UTC
Location: Louisville, Kentucky, USA, Mars. HA!
Contact:

Re: 2048: "Curve-Fitting"

Postby SecondTalon » Fri Sep 28, 2018 1:44 am UTC

Read

The goddamn

Rules

The Goddamn Rules wrote:3. You cannot post any links before you have reached five posts.

Please do not post any links or perform any form of self-promotion until you have a post count of at least five. We have our reasons. Not all spammers are bots, and it can be hard to tell the difference between somebody pointing out somebody else's cool webpage, somebody advertising out their cool webpage, or someone posting malicious links. Because of this, if you have any links in your first post, the entire post will be deleted. Also, pushing your post count up to five with useless posts and then posting your link and vanishing will go over poorly.

“But my link was relevant to the conversation and I think by post was blocked without a moderator even reading it!”

Oh. Gosh. Whatever shall we do. A moderator didn’t read an entire post before blocking it. Gosh. If only there were rules explaining this that should have been read first. Gee golly. What a shame.

That said, there is a list of acceptable and unacceptable words or fragments that first time posters can and cannot use. www will be immediately flagged as spam, as will .com or http. This means that if you fail to hit space between a period and the word commence, it will be blocked as spam as it hits the ".com" flag. You will get a message stating "This message has been flagged as spam and has been blocked" if you attempt to do so. This will go away once you have a few posts under your belt. We do apologize for this inconvenience, but your momentary inconvenience is outweighed by our convenience of not having to block 500+ spam messages a day.

And no, the list of blocked words will not be made public.
heuristically_alone wrote:I want to write a DnD campaign and play it by myself and DM it myself.
heuristically_alone wrote:I have been informed that this is called writing a book.


Return to “Individual XKCD Comic Threads”

Who is online

Users browsing this forum: No registered users and 29 guests