This is one of my favorites:
One entry per answer. (This is in the vein of the Stack Overflow question What’s your favorite “programmer” cartoon?.)
P.S. Do not hotlink the cartoon without the site's permission please.
Was XKCD, so time for Dilbert:
My favourite Dilbert cartoon:
One more Dilbert cartoon:
One of my favorites from xckd:
RFC 1149.5 specifies 4 as the standard IEEE-vetted random number.
From: A visual comparison of normal and paranormal distributions Matthew Freeman J Epidemiol Community Health 2006;60:6. Lower caption says 'Paranormal Distribution' - no idea why the graphical artifact is occuring.
'So, uh, we did the green study again and got no link. It was probably a--' 'RESEARCH CONFLICTED ON GREEN JELLY BEAN/ACNE LINK; MORE STUDY RECOMMENDED!'
I just came across this and loved it:
Another from xkcd #833:
And if you labeled your axes, I could tell you exactly how MUCH better.
By the third trimester, there will be hundreds of babies inside you.
Also from XKCD
This isn't technically a cartoon, but close enough:
There is this one on Bayesian learning:
Nice. The importance of variance when thinking about a population.
And another one from xkcd.
The mouseover text:
The contents of any one panel are dependent on the contents of every panel including itself. The graph of panel dependencies is complete and bidirectional, and each node has a loop. The mouseover text has two hundred and forty-two characters.
Here is a nice one (the inadequacy about average ratings)
Another one from xkcd:
Hell, my eighth grade science class managed to conclusively reject it just based on a classroom experiment. It's pretty sad to hear about million-dollar research teams who can't even manage that.
Here's another one from Dilbert:
More about design and power than analysis, but I like this one
I liked this one:
This is probably fun to show in class as well...
Source: unknown. Posted on flowingdata.com.
Found this one in the comments on Andrew Gelman's blog.
This is data analysis in the form of a cartoon, and I find it particularly poignant.
The universe is probably littered with the one-planet graves of cultures which made the sensible economic decision that there's no good reason to go into space--each discovered, studied, and remembered by the ones who made the irrational decision.
Another one from xkcd: