Computerized Adaptive Testing

Progress in MAT

Dr. Wang's article "MAT Implementation" really help me a lot. I wrote programs to verify the simulation done by him, and the results are listed as follow.

This is the correlation matrix among the 6 dimensions of latent traits specified in advance

1.0000 0.8000 0.8000 0.3000 0.3000 -0.4000

0.8000 1.0000 0.7000 0.2000 0.2000 -0.3000

0.8000 0.7000 1.0000 0.1000 0.2000 -0.2000

0.3000 0.2000 0.1000 1.0000 0.7000 -0.2000

0.3000 0.2000 0.2000 0.7000 1.0000 -0.2000

-0.4000 -0.3000 -0.2000 -0.2000 -0.2000 1.0000

I create 1000 examinees whose ability distribution and correlation satisfy the matrix above; also, I create 9 tests as Wang (160, 160, 160, 20, 20, 20, 200, 200, 200). Then, I produce response vectors by Segall (1996)'s way, and 1000 x 6 data samples be gotten.

Correlation coefficients are calculated based on the 1000 x 6 samples to verify if they follow the matrix listed above. The result is shown below:

1.0000 0.8228 0.8296 0.2621 0.2925 -0.3929

0.8228 1.0000 0.7724 0.1970 0.1985 -0.2852

0.8296 0.7724 1.0000 0.1207 0.2224 -0.2302

0.2621 0.1970 0.1207 1.0000 0.6769 -0.1953

0.2925 0.1985 0.2224 0.6769 1.0000 -0.2007

-0.3929 -0.2852 -0.2302 -0.1953 -0.2007 1.0000

Very good simulation! Now, I can continue my job ....

posted by Shunkai Fu @ 10:07 AM