Hi Ole: Thank you very much. This is exactly what I was looking for.
Thanks, David -----Original Message----- From: Ole Ersoy [mailto:[email protected]] Sent: Monday, August 31, 2015 12:42 PM To: Commons Users List Subject: Re: [math] Poisson distribution to show how many ambulances are dispatched per hour Hi David, public static void main(String[] args) { int numberOfAmbulances = 20; PoissonDistribution ambulanceDistribution = new PoissonDistribution(9); for (int dispatched = 0; dispatched <= numberOfAmbulances; dispatched++) { System.out.println("Likelihood of " + dispatched + " ambulances dispatched is " + ambulanceDistribution.probability(dispatched) + "\n"); } } Cheers, - Ole On 08/31/2015 11:21 AM, Kulpanowski, David wrote: > Hi: > I am working on a relatively simple project. I am attempting to > generate a Poisson distribution for the number of ambulances that are > dispatched. I have looked at my database and determined the average number of > ambulances dispatched is 9 How do I get a Poisson distribution to be > generated using the Commons Math? > > The output I am expecting to generate looks like this.... > > Likelihood of 1 ambulance dispatched is 0.005 Likelihood of 2 > ambulances dispatched is 0.015 Likelihood of 3 ambulances dispatched > is 0.034 Likelihood of 4 ambulances dispatched is 0.61 Likelihood of 5 > ambulances dispatched is 0.091 Likelihood of 6 ambulances dispatched > is 0.117 Etc. > > This is probably a very simple programming question for many of you. But for > me as a novice it is not easy. > > So far, here is what I have using Commons Math; > > import org.apache.commons.math3.distribution.PoissonDistribution; > > public class poissonDistribution > { > public static void main(String[] args) > { > PoissonDistribution ambulanceDistribution = new > PoissonDistribution(9); > System.out.println(ambulanceDistribution); > } > } > > The console output is; > "org.apache.commons.math3.distribution.PoissonDistribution@27716f4" > > I did try and take matters into my own hands and write the equation out > (shown below). But I have a very strong preference to use a method provided > by Commons Math. I am much more confident in Commons Math than my own > abilities. > > The following is my code. It works in a fashion, but I am not > confident in it. Shown below is what I am currently using - but prefer > to avoid using this; import java.lang.Math; public class > PoissonExperiment1 { > public static void main(String[] args) > { > // c is the average number of calls per hour. This is a > variable that is > // derived from your database. > double c = 9.0; > // k is the number of expected calls we want to determine the > probability > int k = 1; > while (k <= 20) > { > int factorialResult = 1; > for (int i = 1; i <= k; i++) > { > factorialResult = factorialResult * i; > } > double term1 = (Math.pow(Math.E, -c)); > double term2 = Math.pow(c, k); > double numerator = term1 * term2; > double answer = numerator / factorialResult; > System.out.format("%10.3f:%n ", answer); > k++; > } > } > } > > > Thank you for your consideration and time, David > > David Kulpanowski > Database Analyst > Lee County Public Safety > PO Box 398 > Fort Myers, FL 33902 > [email protected] > 239-533-3962 > > > > ________________________________ > Please note: Florida has a very broad public records law. Most written > communications to or from County Employees and officials regarding County > business are public records available to the public and media upon request. > Your email communication may be subject to public disclosure. > > Under Florida law, email addresses are public records. If you do not want > your email address released in response to a public records request, do not > send electronic mail to this entity. Instead, contact this office by phone or > in writing. > --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
