Updated T test demo

git-svn-id: https://pmtk3.googlecode.com/svn/trunk@2838 b6abd7f4-f95b-11de-aa3c-59de0406b4f5

demos/bayesTtestDemo.m

@@ -5,11 +5,25 @@
 
 % This file is from pmtk3.googlecode.com
 
+%PMTKneedsStatsToolbox tcdf, ttest
+
 z = [ 30.02, 29.99, 30.11, 29.97, 30.01, 29.99];
 y = [ 29.89, 29.93, 29.72, 29.98, 30.02, 29.98];
 
+% Method based on posterior distribution
+x = z-y;
+N = length(x);
+t = mean(x)./(std(x)/sqrt(N));
+dof = N-1;
+probH1 = 1-tcdf(t, dof) % prob mu>0
+
+% Frequentist method
+[h,pval] = ttest(x, 0, 0.95, 'right')
+assert(approxeq(probH1, pval))
+
+% Method based on Bayes factors
 [BF01, probH0] = bayesTtestOneSample(y-z)
-%% Compare to web program (slightly different prior)
+% Compare to web program (slightly different prior)
 % http://pcl.missouri.edu/sites/default/bf/one-sample.php
 
 

demos/visDirichletGui.m

@@ -18,6 +18,10 @@ function visDirichletGui(arg1)
 
 alpha=[ 2 2 2];
 
+%alpha=0.1*ones(1,3);
+
+end
+
 % compute a fine triangulation of 2-simplex
 disp('Triangulating...');
 res=200;
@@ -39,7 +43,8 @@ function visDirichletGui(arg1)
         pts(counter,:)=p;
         tris2d(counter,:)=[u v];
         tris(counter,:)=p;
-        map(counter) = prod(p.^(alpha-1));
+        %map(counter) = prod(p.^(alpha-1));
+        map(counter) = exp(dirichletLogprob(alpha, [u v]));
     end
 end
 tris=tris(1:counter,:);