Diagnostic test evaluation and comparison
    
   	Numbers of false positives to a test
        
	This utility calculates the expected probability of numbers of false positive results
           to a test for a given sample size and test specificity, assuming the sample is from an uninfected population. It answers the question:
           
For a given sample size and test specificity, and assuming that all animals are uninfected, what is the probability that there will be 1, 2, 3 etc false positives? .
           It also answers the related questions: 
What is the probability of x (1, 2, 3, etc) or more false positive results? and 
           What is the probability of x (1, 2, 3, etc) or less false positive results?.
    
	Inputs:
         
              - Test unit specificity; and
 
              - Sample size.
 
          
    
    
	Outputs:
	A table and plot of probabilities for each of the following:
         
              - the likely numbers of false positives (x);
 
              - less than or equal to x false positives; and;
 
              - greater than or equal to x false positives.