Simple question

[Mack Emmons]

Could someone, really quick, explain the standard derivative and why it is used?

[michi tobler]

Hey Mack, do you mean the standard deviation or derivatives? I don't think there is such a thing as a standard derivative; except in the sense that there is some basic derivatives for simple functions that students are forced to learn in calculus.
Cheers, m

[Bas Pels]

Standard deviation (SD) tells you about the spread around an average.

If I tell you the averige length of a human male is 1.70 meters - you still have not a clue whether a 1.90 meter male is normal or not.

If you have a SD of 90 % with a size of 20 cm - you know 90 % of all males fit within 1.50 to 1.90 meters

were the SD 10 cm - the same male would no longer be 'normal'

@ how to calculate it - I'm happy to say I forgot

[Dan Woodland]

Could someone, really quick, explain the standard derivative and why it is used?

It's all over the web.... here is one example. http://hubpages.com/hub/stddev

[Mack Emmons]

Well, this is embarassing. I must have misread it because the font, thank you for the explanation.