File talk:Standard deviation diagram.svg

2.7% not 2.1% for between 2 and 3 sd (I think!)

Nope, I just checked. It is approximately 2.14002339165491%. (If you have R, type (pnorm(3)-pnorm(2))*100 for this answer.) +mt 04:17, 11 August 2008 (UTC)

Problem with tail

The problem is with the tail. It should read 0.2% (actually more or less 0.175, but round to 0.2 will do), not 0.1%. That is why the sum does not add to 100%. I've recreated the 2000px image with the modification, but I never uploaded one before, so I don't know how. User:Behco

The reason that

$34.1+13.6+2.1+0.1=49.9$

and not 50.0 is that several of these numbers have been rounded down to make a tidy figure. (You can then round 49.9 up to 50.0 for a proper sum for each half of the bell curve.) Where did you get 0.175% from? My calculation for the remainder tail from SD ±3 is 0.1349898% (R: pnorm(-3)*100). +mt 11:12, 18 September 2011 (UTC)