Editing 1374: Urn
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==Explanation== | ==Explanation== | ||
| − | A common | + | A common scenario for teaching elementary probability theory is drawing coloured balls from a container, such as a bag, or hat. In older scenarios, urns were a popular container. |
| − | While an {{w|urn}} can have many uses, | + | While an {{w|urn}} can have many uses, many people assume it is being used as a {{w|cremation}} urn unless otherwise specified. This may be due to a shift in vernacular where the complete term "cremation urn" was shortened to "urn". |
| − | [[Megan]], when asked to imagine drawing balls from an urn, imagines | + | [[Megan]], when asked to imagine drawing balls from an urn, imagines an urn containing not only balls, but also human remains. One could speculate that her grandfather recently died, leading her to make this irrational connection. It's also possible that she's simply bored and trolling [[Cueball]]. |
| − | The title text refers to two distinct scenarios in the | + | The title text refers to two distinct scenarios in the coloured ball experiment: The balls may be replaced between each drawing, or not. In the former case, each draw is independent of the previous, in the latter the chances of picking a particular (remaining) ball the next time have increased. Megan (or rather [[Randall]] if it is he who speaks in the title text) would prefer to put the ashes back into the urn. She might also want to have her grandfather back, and be playing with the word "replacement". |
| − | The distinction between repeated drawing with and without replacement is used in most presentations of elementary probability because it illustrates a subtle but important theoretical distinction: if the balls are replaced, one at a time, before drawing the next, the number of balls of a certain | + | The distinction between repeated drawing with and without replacement is used in most presentations of elementary probability because it illustrates a subtle but important theoretical distinction: if the balls are replaced, one at a time, before drawing the next, the number of balls of a certain colour has the [http://en.wikipedia.org/wiki/Binomial_distribution binomial distribution], but if the balls are not replaced, so that the same ball cannot be drawn twice, you instead get the [http://en.wikipedia.org/wiki/Hypergeometric_distribution hypergeometric distribution]. |
| − | + | The timing of this comic comes during a media popularity of the idea of trigger warnings in classrooms. The idea that teachers should be warning students about any and all concepts from the class that may cause traumatic associations for them. Randall appears to be mocking this by taking it to a logical extreme. | |
==Transcript== | ==Transcript== | ||
:[Cueball is standing in a classroom with Megan at a desk.] | :[Cueball is standing in a classroom with Megan at a desk.] | ||
:Cueball: Imagine that you're drawing at random from an urn containing fifteen balls - six red and nine black. | :Cueball: Imagine that you're drawing at random from an urn containing fifteen balls - six red and nine black. | ||
| − | :Megan: OK. I reach in and... '''''...My grandfather's ashes?!?''' Oh | + | :Megan: OK. I reach in and... '''''...My grandfather's ashes?!?''' Oh god!'' |
:Cueball: I... what? | :Cueball: I... what? | ||
:Megan: '''''Why would you do this to me?!?''''' | :Megan: '''''Why would you do this to me?!?''''' | ||
