Re: Probability Density Function

*To*: mathgroup at smc.vnet.net*Subject*: [mg74817] Re: Probability Density Function*From*: "Ray Koopman" <koopman at sfu.ca>*Date*: Fri, 6 Apr 2007 04:23:17 -0400 (EDT)*References*: <ev2beo$kl0$1@smc.vnet.net>

On Apr 5, 1:19 am, "Tony Harris" <tdh1... at bellsouth.net> wrote: > Hello, > > I have graphed a normal probability density function with a mean of 10 and a > standard deviation of 2.5. I named this function f[x] > > I wanted to know how to use the "FilledPlot" to show the area under the > curve for (x<8) and (7.5<x<11). > > I have the probability for x<8 to be .212 and for 7.5<x<11 to be .497 by > calculating the definite integral of the function f[x] for these two > probabilities. > > I have the cacluation of the probabilities included but no idea on how to > continue and display each of these in a graph. > > Thanks, > > T Harris << Graphics`FilledPlot` f[x_,m_,s_] := Exp[-.5((x-m)/s)^2]/(s*Sqrt[2Pi]) FilledPlot[{f[x,10,2.5],f[x,10,2.5]*UnitStep[8-x]},{x,0,20}, Fills->{{{2,Axis},GrayLevel[.75]}}]; FilledPlot[{f[x,10,2.5],f[x,10,2.5]*UnitStep[(x-7.5)(11-x)]},{x, 0,20}, Fills->{{{2,Axis},GrayLevel[.75]}}];