Open Side Menu Go to the Top
Register
Probably a basic and dumb standard deviation question.... Probably a basic and dumb standard deviation question....

06-11-2015 , 06:40 PM
So, I have a distribution of numbers that doesn't appear to be normal...as in it doesn't fit the conventional bell curve. Rather, the curve peaks much further to the left and trails off for a while out to the right.

To add some additional context, across a population of several million widgets, they have a min/avg/max of 1 / 2000 / 2.5 million. The calculated standard deviation for my example population is something like 37,000+, which is a pretty large number compared to the avg.

My very basic and dumb question is: is standard deviation even a useful metric worth reporting on when the distribution is non-normal? Would it be correct that the usefulness of standard deviation diminishes as the normality of a distribution decreases?

Thanks, in advance!

Last edited by JinX11; 06-11-2015 at 06:56 PM.
Probably a basic and dumb standard deviation question.... Quote
06-11-2015 , 06:59 PM
Quote:
Originally Posted by JinX11
So, I have a distribution of numbers that doesn't appear to be normal...as in it doesn't fit the conventional bell curve. Rather, the curve peaks much further to the left and trails off for a while out to the right.

To add some additional context, across a population of several million widgets, they have a min/avg/max of 1 / 2000 / 2.5 million. The calculated standard deviation for my example population is something like 37,000+, which is a pretty large number compared to the avg.

My very basic and dumb question is: is standard deviation even a useful metric worth reporting on when the distribution is non-normal? Would it be correct that the standard deviation becomes less and less useful as the normality of a distribution decreases?

Thanks, in advance!
Standard deviation and variance are meaningful for non-normal distributions, but their meaning is not as straightforward. I would recommend ready about Chebyshev's Inequality for an application to non-normal distributions.
Probably a basic and dumb standard deviation question.... Quote
06-11-2015 , 07:43 PM
Many distributions can have a right-handed tail, one of them being the lognormal. This distribution is characterized by the logarithm of the variate being normally distributed. Check it out on Wikipedia or other internet sites.
Probably a basic and dumb standard deviation question.... Quote

      
m