--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rDiff/src/tests/comp_nbin_p_value_mean_variance.m	Thu Feb 14 23:38:36 2013 -0500
@@ -0,0 +1,31 @@
+function [P_VALUE,FLAG_ERR]=comp_nbin_p_value_mean_variance(MEAN1,MEAN2,SIGMA1,SIGMA2,COUNTS1,COUNTS2)
+%This function computes the p_value for a negative binomial
+%hypothesis test given the mean and variance of two nbin
+%distributions and counts from the respective distributions
+
+  FLAG_ERR=0;
+  r1=(MEAN1^2)/(SIGMA1-MEAN1);
+  p1=1-(MEAN1/(SIGMA1));
+  r2=(MEAN2^2)/(SIGMA2-MEAN2);
+  p2=1-(MEAN2/(SIGMA2));
+  
+  P_OBS=calcl_nbin_pdf(COUNTS1,r1,1-p1)*calcl_nbin_pdf(COUNTS2,r2,1-p2);
+  
+  
+  P_A=calcl_nbin_pdf(0:(COUNTS1+COUNTS2),r1,1-p1);
+  P_B=calcl_nbin_pdf((COUNTS1+COUNTS2):(-1):0,r2,1-p2);
+  P_COMB=sort(P_A.*P_B);
+
+  if sum(P_COMB)>0
+    POS= find(P_COMB<=P_OBS,1,'last');
+    if isempty(POS)
+      P_VALUE=min(P_COMB);
+    else
+      P_VALUE=sum(P_COMB(1:POS))/sum(P_COMB);
+    end
+  else
+    P_VALUE=1;
+  end
+  
+  
+  
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