881: Probability

2014-01-25T21:15:20Z

Bushiki85: /* Transcript */ changed to 'percent vs. years' to reflect the standard axes naming convention of plotting 'y data' versus 'x data'

{{comic
| number = 881
| date = April 4, 2011
| title = Probability
| image = probability.png
| titletext = My normal approach is useless here, too.
}}

==Explanation==
{{incomplete|The difference between the two lines has to be explained. The "IV drip" is unknown to the most non native English speakers.}}

[[Cueball]] and [[Megan]] are sitting on a hospital bed, reading a piece of paper with the statistics for {{w|breast cancer}} survival. It looks like Megan has just been diagnosed with breast cancer. The thick line represents the survival rate distribution (probability to be alive after X years, unconditioned): 81% are alive at 5 years, while 77% survive to 10 years. The dashed line represents the {{w|hazard function}} (in very loose terms, the risk of failing/dying at time t+delta after having survived until time t), which is the rate between the density of the failure distribution and the survival function.

[[Randall]] wrote this comic after his fiancee was diagnosed with breast cancer. Two months after posting this strip, he posted [http://blog.xkcd.com/2011/06/30/family-illness/ this blog post] explaining the cancer strips.

The title text could be a reference to the comic [[55: Useless]]. Cueball's (and [[Randall]]'s) normal approach — math — isn't much help in dealing with ''this'' emotional situation, either. The phrase "normal approach" may also in this case be a pun on the {{w|Normal distribution}}, which is another probability distribution that is commonly used in statistics. Interpreted this way, the title text states that the "Normal distribution" is not used as a hazard function.

==Transcript==
:[A plot of percent vs. years, with a solid and a dashed line. The solid line starts at 100%, and drops constantly. The dashed line starts around 85%, rises to 95% after 5 years, then drops.]

:[A simple table.]
:{| class="wikitable"
|-
|  5 years
| 81%
|-
| 10 years
| 77%
|}

:[Cueball and Megan are sitting on a bench, next to an IV drip hanging from a rack. Cueball is holding a paper.]
:Cueball: You know, probability used to be my favorite branch of math
:Cueball: Because it had so many real-life applications.

:[They embrace, faces together.]

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Romance]]
[[Category:Cancer]]
[[Category:Charts]]
[[Category:Math]]
[[Category:Statistics]]

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881: Probability