User:NHSavage/Sandbox

Explanation

In this comic, Megan and Cueball come to see some scientists to investigate their theory that jelly beans cause acne. The scientists of course do not want to stop playing the addictive game Minecraft (which has been referenced in a previous xkcd).

When the scientists come back and say there is no link between jelly beans and acne, Megan and Cueball have heard that it is specific colors that cause acne. So, the scientists tear themselves away from Minecraft again and study each and every color (including mauve and turquoise - I didn't know those were real colors for jelly beans). Green is the only color that has any link. So, obviously the news blows the coverage out of control, even though as we see in the image text that the green jelly beans study may have been a coincidence.

But, of course, the news coverage in all caps in the image text blows it out of proportion again.

More to the point, the scientists studied 20 different colors, and only one showed a link at the 95% confidence level. The 95% confidence level MEANS that there is a 95% chance that the link is not random. So by definition we would expect 1 out of 20 studies to show a link at this level by pure random chance. This is a big problem in correlation research generally, because scientists study many different possible causal factors, and then report the ones that show significance. Without a plausable causation mechanism it’s not clear what value such studies have, given that 1/20 will randomly show a correlation at (p>.05). For more: http://www.fallacyfiles.org/multcomp.html

Also comment on media coverage of science.

Transcript

[Person with a pony tail runs up to another person, who subsequently points off-panel where there are presumably scientists.]

Ponytail: Jelly beans cause acne!

Another: Scientists! Investigate!

Scientists: But we&'re playing Minecraft!

Scientists: ... Fine.

[Two scientists. One has safety goggles, the other has a sheet of notes.]

Goggles: We found no link between jelly beans and acne (p > 0.05).

[Back to the original two.]

Another: That settles that.

Ponytail: I hear it's only a certain color that causes it.

Another: Scientists!

Scientists: But Miiiinecraft!

[20 near identical small panels follow, 4 rows 5 columns.]

Goggles: We found no link between purple jelly beans and acne (p > 0.05).

Goggles: We found no link between brown jelly beans and acne (p > 0.05).

Goggles: We found no link between pink jelly beans and acne (p > 0.05).

Goggles: We found no link between blue jelly beans and acne (p > 0.05).

Goggles: We found no link between teal jelly beans and acne (p > 0.05).

Goggles: We found no link between salmon jelly beans and acne (p > 0.05).

Goggles: We found no link between red jelly beans and acne (p > 0.05).

Goggles: We found no link between turquoise jelly beans and acne (p > 0.05).

Goggles: We found no link between magenta jelly beans and acne (p > 0.05).

Goggles: We found no link between yellow jelly beans and acne (p > 0.05).

Goggles: We found no link between grey jelly beans and acne (p > 0.05).

Goggles: We found no link between tan jelly beans and acne (p > 0.05).

Goggles: We found no link between cyan jelly beans and acne (p > 0.05).

Goggles: We found a link between green jelly beans and acne (p < 0.05).

Off-panel: WHOA!

Goggles: We found no link between yellow jelly beans and acne (p > 0.05).

Goggles: We found no link between beige jelly beans and acne (p > 0.05).

Goggles: We found no link between lilac jelly beans and acne (p > 0.05).

Goggles: We found no link between black jelly beans and acne (p > 0.05).

Goggles: We found no link between peach jelly beans and acne (p > 0.05).

Goggles: We found no link between orange jelly beans and acne (p > 0.05).

[Newspaper front page.]

NEWS Green Jelly Beans Linked To Acne! 95% Confidence

[There is a picture of 3 green jelly beans.]

Only 5% chance of coincidence!

Scientists...

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