这将区分上面的点以下 threshhold1 ：

  plot（aH，loglik（loglik> = threshold1），'r。'）; 
坚持; 
 plot（aH，loglik（loglik< threshold1），'b。'）; 
 

以上（或等于） threshhold1 是红色，下面是蓝色。

After running the program, I got 14 values of loglik, then I plotted these value within two lines. The code is below:

loglik=[-3168.7176,-4644.451,-3759.7372,-1758.1307,-4813.0647,-4147.0188,...
        -4330.944,-4612.9895,-3829.8987,-2687.4927,...
        -4007.5629,-2799.527,-2747.96,4.386];
aH = axes;
plot(aH,loglik,'r.'); hold on;
threshold1=mean(loglik)+1*std(loglik);
threshold2=mean(loglik)+3*std(loglik);
plot(aH, aH.XLim, [threshold2, threshold2], 'r-');
plot(aH, aH.XLim, [threshold1, threshold1], 'r-');

Now, I want to identify the points which are below threshold1. How can I do that?

This will distinguish visually between the points above\below threshhold1:

plot(aH,loglik(loglik>=threshold1),'r.');
hold on;
plot(aH,loglik(loglik<threshold1),'b.');

Points above (or equal to) threshhold1 are red, and below are blue.