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Class size for the 21 trended anchor items in 1999, 2003, and 2007 TIMSS using two-class mixture 3PL IRT model.
| 1999 | 2003 | 2007 | |
|---|---|---|---|
| Class 1 | 0.04 (0.01) | 0.19 (0.01) | 0.10 (0.01) |
| Class 2 | 0.96 (0.01) | 0.81 (0.01) | 0.90 (0.01) |
| Var(θ) | 2.27 (0.07) | 0.74 (0.01) | 1.76 (0.05) |
Values in parenthesis represent MC Error.
