function analyze_2d(data1,data2,IHD,ALL_CATEGORIES)
data2=abs(data2);
% plots data1 vs data2 pairs and sample mean and covariance

    num_params=size(data1,2);

    for param_idx=1:num_params
%         mean_all=MEAN_DATA_ALL(:,param_idx);
%         mean_1=MEAN_DATA_ALL(IHD==1,param_idx);
%         mean_0=MEAN_DATA_ALL(IHD==0,param_idx);
%         
%         
%         isnan1=sum(~isnan(MEAN_DATA_ALL(IHD==1,param_idx)))/(sum(IHD==1));
%         isnan0=sum(~isnan(MEAN_DATA_ALL(IHD==0,param_idx)))/(sum(IHD==0));
%         
%         M1 = mode(mean_1);
%         M0 = mode(mean_0);
        
%         figure(param_idx)
%         
%         subplot(1,3,1)
%         hist(mean_all)
%         title([ALL_CATEGORIES{param_idx} ' all'])
%         
%         
%         subplot(1,3,2)
%         hist(mean_1)   
%         title([ALL_CATEGORIES{param_idx} ' 1'])
%        
%         
%         subplot(1,3,3)
%         hist(mean_0)    
%         title([ALL_CATEGORIES{param_idx} ' 0'])
        
%         figure(param_idx+num_params+5)
%         hist(mean_1,20)
%         h = findobj(gca,'Type','patch');
%         set(h,'FaceColor','r','EdgeColor','w','facealpha',0.75)
%         hold on;
%         hist(mean_0,20)
%         h1 = findobj(gca,'Type','patch');
%         set(h1,'facealpha',0.75);
%         title([ALL_CATEGORIES{param_idx} ' mode0=' num2str(M0) '. '  ' mode1=' num2str(M1)]);
% 

%      
IHD2=IHD(~isnan(data1(:,param_idx)) & ~isnan(data2(:,param_idx)));
x=data1(~isnan(data1(:,param_idx)) & ~isnan(data2(:,param_idx)),param_idx);
mx0=mean(x(IHD2==0));
mx1=mean(x(IHD2==1));
y=data2(~isnan(data1(:,param_idx)) & ~isnan(data2(:,param_idx)),param_idx);
my0=mean(y(IHD2==0));
my1=mean(y(IHD2==1));


C0=cov(x(IHD2==0),y(IHD2==0));
eig(C0)
[pc1,score1,latent1,tsquare1] = princomp([x(IHD2==0) y(IHD2==0)]);

C1=cov(x(IHD2==1),y(IHD2==1));
[pc2,score2,latent2,tsquare2] = princomp([x(IHD2==1) y(IHD2==1)]);
        


figure(param_idx+num_params+5)
        
        
%         scatter(data1(IHD==0,param_idx),data2(IHD==0,param_idx),'xr')
%         hold on
%         scatter(data1(IHD==1,param_idx),data2(IHD==1,param_idx),'ob')

      
        
        scatter(x(IHD2==0),y(IHD2==0),'bx')
         hold on
         scatter(mx0,my0,'LineWidth',2,'MarkerEdgeColor','g')
        CosTheta = dot(pc1(:,1),[1 0]')/(norm(pc1(:,1))*norm([1 0]'));
        phi = acos(CosTheta);

      %  pdeellip(mx0,my0,latent(1),latent(2),phi) 
        
        
         h=ellipse(latent1(1),latent1(2),phi,mx0,my0,'b');
        
       
         scatter(x(IHD2==1),y(IHD2==1),'rx')
    scatter(mx1,my1,'LineWidth',2,'MarkerEdgeColor','g')
         CosTheta = dot(pc2(:,1),[1 0]')/(norm(pc2(:,1))*norm([1 0]'));
        phi = acos(CosTheta);

      %  pdeellip(mx0,my0,latent(1),latent(2),phi) 
        
        
         h=ellipse(latent1(1),latent1(2),phi,mx1,my1,'r');
  
        title([ALL_CATEGORIES{param_idx}]);

     
        
        
        
        
        
%         data = rand(1, 100);
% [N, X] = hist(data, 0:0.1:1);
% 
% subplot(2, 1, 1);
% hist(data, 0:0.1:1);
% 
% subplot(2, 1, 2);
% bar(X, N./sum(N), 1);
        
    end




end