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A
Anonymous
January 20, 2010
Question

How to skew a normal Distribution?

  • January 20, 2010
  • 3 replies
  • 14480 views
I have a attached a rather simple MathCAD sheet (V13) with a rnorm distribution plotted. Can someone suggest how I would go about creating a skew distribution over the same range with the peak a approximately in the first third of the graph?

Thank-you in advance

David

3 replies

R
RichardJ19-Tanzanite
19-Tanzanite
January 20, 2010
The easiest approach would probably be to multiply it by a ramp function.

Richard
T
TomGutman1-Visitor
1-Visitor
January 21, 2010
You don't skew a normal distribution. You choose a different distribution to start. You should be defining the relevant range based on the underlying model. Depending on other factors, perhaps a Weibull or a beta distribution might fit your needs. But start with your model, and work from there to determine the appropriate distribution.
__________________
� � � � Tom Gutman
P
PhilipOakley1-Visitor
1-Visitor
January 21, 2010
Try some of the wikipedia approximations for other distributions that are skewed (as Tom suggests).



Philip Oakley
A
Anonymous
January 22, 2010
I like to thank everyone who has taken the time to post a response to my question. I have created a monte carlo simulation of which I could use some easy way to create a distribution that appears skewed, hence my question.

Richard: I will try using some sort of ramp function to see if I can get what I am looking for.

jmG: I have attached a new file saved as MathCAD 11 (as requested). I thank-you for any help you may be able to provide me.

Tom: I did not use the distributions you suggested as the data created is related to a "shape" argument. The rnorm function creates the data based on a mean value and Standard Deviation. I suppose I could use the Weibull distribution but I will have to covert the values to fall within the range I am looking for.

P
ptc-13682881-Visitor
1-Visitor
January 21, 2010
On 1/20/2010 3:51:24 PM, dsanz905 wrote:
>I have a attached a rather
>simple MathCAD sheet (V13)
>with a rnorm distribution
>plotted.
> ...
>David
__________________________

Years ago, I have designed an "assymetric normal" for Leslie (PTC).
I can't try because you didn't "Save as" 11 as recommended by two collabs.

jmG



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