Analysis of Variance for Item Differences in Verification Data with Unknown Groups

Table 1

Performance of estimators of for several values of and . The true values are , and negative estimates of are allowed. The RMSEs for =3, =16 agree with that predicted by (6) for merging successive groups, and the RMSEs for =12, = 4 agree with that predicted by (7) for splitting each group into 2 groups.

	Percent relative bias in	Percent relative RMSE in
=6, =8 (correct)	0, 0, 0	22, 96, 24
=2, =24	8, -45, 0	32,99,25
=24, =2	0, -7, -1	29,114,23
=3, =16	7, -32, 0	29,92,25
=12, =4	0,-5,-1	24,95,23
MAD,FAP=0.1	0,5,1	25,103,25
MAD, FAP=0.05	3,-6,1	26,101,26
MAD, FAP=0.01	1, 0, 1	25,102,25