R help - Jul 2008 - Howto Draw Bimodal Gamma Curve with User Supplied Parameters

Hi,

Suppose I have the following vector (data points):
> x
  [1]  36.0  57.3  73.3  92.0 300.4  80.9  19.8  31.4  85.8  44.9  24.6  48.0
 [13]  28.0  38.3  85.2 103.6 154.4 128.5  38.3  72.4 122.7 123.1  41.8  21.7
 [25] 143.6 120.2  46.6  29.2  44.8  25.0  57.3  96.4  29.4  62.9  66.4  30.0
 [37]  24.1  14.8  56.6 102.4 117.5  90.4  37.2  79.6  27.8  17.1  26.6  16.3
 [49]  41.4  48.9  24.1  23.3   9.9  11.5  15.0  23.6  29.3  27.0  19.2  18.7
 [61]   4.1  13.0   3.3   5.5  38.2   8.5  39.6  39.2  16.1  35.3  23.3  31.5
 [73]  38.8  51.5  28.4  18.8  24.1  25.4  28.8  32.8  31.0  28.8  33.3  55.5
 [85]  39.2  21.0  43.7  16.3  50.6  34.6  66.3  50.5  59.4  46.7  51.9 125.6
 [97]  69.8  43.7  86.8  50.6 132.4  56.0   6.1   4.9   7.1   7.1  12.8  12.1
[109] 164.2  69.3  15.6  11.4  34.3   9.2  17.6  21.7  19.2  30.7  61.1  35.8
[121] 185.8 118.4  13.0   9.6  19.1  45.2  94.5 248.0  56.3  24.4  13.8  12.8
[133]  35.0  31.6  22.5  50.1  18.7  22.1  28.3  39.5  48.2  33.1  43.5  35.1
[145]  37.4  30.3  15.8  13.9  15.3  16.1  12.7  11.4  13.0  13.8  31.5  25.3
[157]  65.2  39.5


And the following parameter set (2 component) for gamma function.

                             comp.1    comp.2
alpha (shape)  2.855444  2.152056
beta  (scale)   10.418785 39.296224

These params are predefined/precalculated by user.

My question is how can I create a bimodal gamma curve - based on the
two parameter set -
on top of the histogram of data points above?

- Gundala Viswanath
Jakarta - Indonesia

can you write the bimodal gamma pdf?
if so create your own pdf:

dbigamma=function(x,alpha1,alpha2,beta1,beta2)
{
# ... the bimodal gamma pdf (I can't find it)
}

hist(x,probability=T)
curve(dbigamma(x,alpha1,alpha2,beta1,beta2))

and look at the result

regards,

PF

2008/7/29 Gundala Viswanath <gundalav at
gmail.com>:
> Hi,
>
> Suppose I have the following vector (data points):
>> x
>  [1]  36.0  57.3  73.3  92.0 300.4  80.9  19.8  31.4  85.8  44.9  24.6 
48.0
>  [13]  28.0  38.3  85.2 103.6 154.4 128.5  38.3  72.4 122.7 123.1  41.8 
21.7
>  [25] 143.6 120.2  46.6  29.2  44.8  25.0  57.3  96.4  29.4  62.9  66.4 
30.0
>  [37]  24.1  14.8  56.6 102.4 117.5  90.4  37.2  79.6  27.8  17.1  26.6 
16.3
>  [49]  41.4  48.9  24.1  23.3   9.9  11.5  15.0  23.6  29.3  27.0  19.2 
18.7
>  [61]   4.1  13.0   3.3   5.5  38.2   8.5  39.6  39.2  16.1  35.3  23.3 
31.5
>  [73]  38.8  51.5  28.4  18.8  24.1  25.4  28.8  32.8  31.0  28.8  33.3 
55.5
>  [85]  39.2  21.0  43.7  16.3  50.6  34.6  66.3  50.5  59.4  46.7  51.9
125.6
>  [97]  69.8  43.7  86.8  50.6 132.4  56.0   6.1   4.9   7.1   7.1  12.8 
12.1
> [109] 164.2  69.3  15.6  11.4  34.3   9.2  17.6  21.7  19.2  30.7  61.1 
35.8
> [121] 185.8 118.4  13.0   9.6  19.1  45.2  94.5 248.0  56.3  24.4  13.8 
12.8
> [133]  35.0  31.6  22.5  50.1  18.7  22.1  28.3  39.5  48.2  33.1  43.5 
35.1
> [145]  37.4  30.3  15.8  13.9  15.3  16.1  12.7  11.4  13.0  13.8  31.5 
25.3
> [157]  65.2  39.5
>
>
> And the following parameter set (2 component) for gamma function.
>
>                             comp.1    comp.2
> alpha (shape)  2.855444  2.152056
> beta  (scale)   10.418785 39.296224
>
> These params are predefined/precalculated by user.
>
> My question is how can I create a bimodal gamma curve - based on the
> two parameter set -
> on top of the histogram of data points above?
>
> - Gundala Viswanath
> Jakarta - Indonesia
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>