R help - Aug 2007 - Can I calculcate the percentage of a gamma function area below a cutoff value?

Hi there,

 

I have some bird flight height data that follows a gamma distribution.  The
data (x) goes from 0 to 700 meters (n=1055).  The calculated parameters
calculated from the fitdistr(x) are (shape = 5.1379, rate = 0.017541), and
therefore the scale (1/rate) = 57.00929.  I would like to calculate the
percentage of the function area that occurs below 50 meters (0-50m).  

 

Is that possible?  

Thanks!

 

 

Jake Verschuyl
Ecologist

P.O. Box 2561, Mount Vernon, WA 98273

Tel: 360.899.5156

Fax: 360.899.5146 

P Please consider the environment before printing this email.

 


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Hi

Jake Verschuyl wrote:
> Hi there,
> 
>  
> 
> I have some bird flight height data that follows a gamma distribution.  The
> data (x) goes from 0 to 700 meters (n=1055).  The calculated parameters
> calculated from the fitdistr(x) are (shape = 5.1379, rate = 0.017541), and
> therefore the scale (1/rate) = 57.00929.  I would like to calculate the
> percentage of the function area that occurs below 50 meters (0-50m).  
> 
I guess
?pgamma
will help you?

and in your case:
pgamma(q=50, shape = 5.1379, rate = 0.017541)
 > pgamma(q=50, shape = 5.1379, rate = 0.017541)
[1] 0.001620588
 > pgamma(700, shape = 5.1379, rate = 0.017541)
[1] 0.9927367

Was this what you were looking for?

 >
 > P Please consider the environment before printing this email.
 >
 >
Don't worry, I will not print it. And in return:
Please consider reading the posting guide...
where it is stated:
=> Read at least the relevant section in "An Introduction to R"

There is a section (Section 8) which answers (almost) all questions on 
probability distributions and R.

Best,
Roland