program to calculate male to female ratio of a given number

/** 
  * Write a description of class HeadsOrTailsV1 here. 
  *  
  * @author (your name)  
  * @version (a version number or a date) 
  */  
 import java.util.Scanner;  
 import java.util.Random;
 public class PopulationRatio
{  
   public static void main(String [] args)
   {
       Scanner in;  
         in = new Scanner(System.in);  
           
         System.out.println("Enter the number of People: "); 
         int numberOfPeople = in.nextInt();  
         int numberOfMen = 0;  
         int numberOfWomen = 0; 
         double randomNumber = 0;  
         int counter = 0;        
         
         System.out.println("\n");
         
         while(counter <= numberOfPeople)  
         {  
             randomNumber = Math.random(); 
             numberOfWomen = numberOfPeople - numberOfMen;
             counter ++;  
               
               
             boolean isMale = randomNumber > .5;  
               
             if (isMale)  {  
                 System.out.print("\nM: " + randomNumber);  
                 numberOfMen++;
             }  
             else {   
                 System.out.print("\nW: " + randomNumber);  
                 numberOfWomen++;
                }
             }
             System.out.print("\n");
             System.out.println("The number of Men equals: " + numberOfMen);
             System.out.println("The number of Women equals: " + numberOfWomen);
        }      
 }

i have the following code, and it works correctly, but im not sure how to make the results be partially biased towards the male side to represent the slightly greater number of males in the world. it is male: 50.34%, female: 49.66%. how can i incorporate this into the program? examples are welcome. thank you in advance.

Before even thinking about writing a line of code, you should work out the math behind the problem. Give that a go.

nathan gibson wrote:boolean isMale = randomNumber > .5;

Just as a side note, you do know that the changes of being a female are larger than those of being a male this way, right?

randomNumber is between 0 (inclusive) and 1 (exclusive). For simplicity's sake let's only deal with steps of 0.01.
Someone is female for all values from 0 to 0.5 (inclusive) - that's 51 different values. Someone is male for all values from 0.51 to 0.99 (inclusive) - that's 49 different values. To have an even 50-50 match, turn the > into a >=.

nathan gibson wrote:it is male: 50.34%, female: 49.66%. how can i incorporate this into the program?

That would be very easy. You'd just have to change one thing in this line:

What do you think you'd have to change there to make the chance of isMale being true to .5034?

Surely that's < 0.5, Jesper???

hi

Let me put this forward this way:

for simplicity, lets assume random gives you a value between 1 to 10 (both inclusive)
assuming that you want ratio of men >= 70% and female <=30%
wouldnt you say that if random <=7 its a Man else a Woman ?

now change the example to match 50.34% with random 0 to 1

oh. okay. i got ya, sorry, that was due to a bit of programmers block, thanks for the help. you guys are great.

Hi nathan,

I've noticed that this is the same program what you posted here. Only the variable names and interpretations are different. Can I ask you what's the purpose of this? I'm really curious.
According to the answers you got here you should also change the randomNumber > .5; to randomNumber >= .5; in the coin flipping program.

Campbell Ritchie wrote:Surely that's < 0.5, Jesper???

I just copied and pasted a line of code out of Nathan's original program.

Jesper Young wrote:I just copied and pasted a line . . .

Which will have well over 0.00000000000001% inaccuracy