Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2004
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2004

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: how to graphically fill the tails of a normal distribution

  • To: mathgroup at smc.vnet.net
  • Subject: [mg50039] Re: [mg50012] how to graphically fill the tails of a normal distribution
  • From: Bob Hanlon <hanlonr at cox.net>
  • Date: Thu, 12 Aug 2004 05:44:12 -0400 (EDT)
  • Reply-to: hanlonr at cox.net
  • Sender: owner-wri-mathgroup at wolfram.com

Needs["Graphics`"];

Needs["Statistics`NormalDistribution`"];

ndist=NormalDistribution[0, 1];

npdf=PDF[ndist,x];

FilledPlot[npdf{1,UnitStep[x+2]-UnitStep[x-2]},
    {x,-4,4},Fills->Red, PlotRange->All];

FilledPlot[npdf{1,If[Abs[x]<2,1,0]},
    {x,-4,4},Fills->Red, PlotRange->All];

FilledPlot[npdf{1,If[-2<x<2,1,0]},
    {x,-4,4},Fills->Red, PlotRange->All];


Bob Hanlon

> 
> From: Todd Allen <genesplicer28 at yahoo.com>
To: mathgroup at smc.vnet.net
> Date: 2004/08/11 Wed AM 05:53:11 EDT
> To: mathgroup at smc.vnet.net
> Subject: [mg50039] [mg50012] how to graphically fill the tails of a normal distribution
> 
> 
> Hello all,
>  
>       Hope you don't mind a question from a biologist trying to learn 
Mathematica.  I have been teaching myself the syntax of Mathematica to 
analyze microarray data (i.e, a technology to simultaneously monitor the 
expression levels of thousands of genes).  I am interested in producing a plot 
for a presentation in which the tails of a normal distribution are colored red 
to illustrate a concept.  I can get the plot to work with a single tail, but I can't 
get the syntax to work for both tails of the disribution.  Here is my code:
>  
> This works for a single tail, with the following code (necessary packages 
already loaded): 
> ndist=NormalDistribution[0,1]
> 
> npdf=PDF[ndist,x]
> 
> FilledPlot[{npdf,If[x³2,0,npdf]},{x,-4,4},Fills®RGBColor[1,0,0]]
> 
> However when I try the following with the Or operator (at least I think Or 
operator):
> 
> FilledPlot[{npdf,If[x³2.0þx£-2.0,0,npdf]},{x,-4,4},Fills®RGBColor[1,0,0]]
> 
> I get a series of error messages: 
> 
> Plot:plnr:If[x³2.0þx£-2.0,0,npdf] is not a machine-size real number at x=
-4
> 
> This error repeats itself with different x values and then a normal curve is 
drawn with neither tail colored in.
> 
> 
>  
> What am I missing here?
>  
> Any insight is much appreciated, thanks!
> Todd
> 


  • Prev by Date: Re: message 50001?
  • Next by Date: Re: how to graphically fill the tails of a normaldistribution
  • Previous by thread: Re: how to graphically fill the tails of a normal distribution
  • Next by thread: RE: how to graphically fill the tails of a normal distribution