Table 6.

Estimates of Category Slopes (${\hat{a}}_{\mathrm{jk}}s$) and Standard Errors, 2D-Nominal Equal Items Model, TIMSS Math and Science Data, Eighth Grade, United States (N = 7,377).

	Math		Science
Category	Dimension 1	Dimension 2	Dimension 1	Dimension 2
1	−0.77 (.02)	−0.28 (.03)	−0.66 (.02)	−0.37 (.03)
2	−0.00 (.02)	0.07 (.03)	0.03 (.01)	−0.08 (.02)
3	0.78 (.02)	0.21 (.03)	0.63 (.02)	0.45 (.03)

Note. TIMSS = Trends in Mathematics and Science Study.