Line 5: Line 5:
 
The code for this graph is like below.
 
The code for this graph is like below.
  
<nowiki>
+
    samples_step = 3;
samples_step = 3;
+
    num_samples = samples_step:samples_step:10000;
num_samples = samples_step:samples_step:10000;
+
    len = length(num_samples);
len = length(num_samples);
+
    mu = 0;
mu = 0;
+
    sigma = 5;
sigma = 5;
+
    muhat = zeros(1, len);
muhat = zeros(1, len);
+
    sigmahat = zeros(1, len);
sigmahat = zeros(1, len);
+
    for x = num_samples
for x = num_samples
+
        data = mu + sigma * randn(1, x);
    data = mu + sigma * randn(1, x);
+
        phat = mle(data(1, :));
    phat = mle(data(1, :));
+
        muhat(1, x/samples_step) = phat(1);
    muhat(1, x/samples_step) = phat(1);
+
        sigmahat(1, x/samples_step) = phat(2);
    sigmahat(1, x/samples_step) = phat(2);
+
    end
end
+
    plot(num_samples, muhat);
plot(num_samples, muhat);
+
    hold on;
hold on;
+
    plot(num_samples, sigmahat);
plot(num_samples, sigmahat);
+
</nowiki>
+
  
 
--[[User:Han84|Han84]] 22:49, 2 April 2010 (UTC)
 
--[[User:Han84|Han84]] 22:49, 2 April 2010 (UTC)

Revision as of 19:06, 2 April 2010

MATLAB has a "mle" function for maximum likelihood estimation. I think that this function is useful to verify the result of hw2 if you have MATLAB. I try to find the effect of the sample size in MLE using "mle" function because the number of samples is critical for estimation. To do this, I generate samples from normal distribution with mean as 0 and std as 5. The below graph shows the results of MLE according to the number of samples.

Mle samples.jpg

The code for this graph is like below.

   samples_step = 3;
   num_samples = samples_step:samples_step:10000;
   len = length(num_samples);
   mu = 0;
   sigma = 5;
   muhat = zeros(1, len);
   sigmahat = zeros(1, len);
   for x = num_samples
       data = mu + sigma * randn(1, x);
       phat = mle(data(1, :));
       muhat(1, x/samples_step) = phat(1);
       sigmahat(1, x/samples_step) = phat(2);
   end
   plot(num_samples, muhat);
   hold on;
   plot(num_samples, sigmahat);

--Han84 22:49, 2 April 2010 (UTC)

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