t'eKa tabyn LOC mannan tannan tabnan ABL mannando tannando tabnandykti COM masse tasse tabse ABES matkalyk tatkalyk tabytkalyk Table 2 Case paradigm of the Middle-Ob Selkup pronouns in the plural Case 1PL 2PL
3PL NOM mi ti tabla GEN mi t'i tablan ACC migyt t'igynt tablap LAT miqynut t'iqyndyt tabland LOC minan t'inan tablanan ABL minando t'inando tablanando COM mize t'ize tablaze ABES mikalk t'ikalk tablakalk
Likelihood ratio tests between fitted nested IRT models showed that the 2PL
model (log-likelihood = -3387.
By having the probabilities L, the next step is to determine the 15 couples of 2PL
parameters (a,b) that minimize the difference between L and the IRT probabilities in order to reduce to minimum the discrepancy between IRT model and the LSDM.
The extent and reasons for the implementation of 2PL
In the Rasch and 2PL
model, information is largest at the place where item difficulty equals examinee ability.
In the 1PL and 2PL
models, the probability of a correct answer approaches 0 in the case of a low-ability student answering a difficult item correctly, and 1 in the case of a high-ability student answering an easy item.
The mathematical form of the 2PL
model could be written as
CORRESSPONDENCE: Asif Rajah, 41 Prospect Lane, Harpenden, Hertfordshire, AL5 2PL
Ann Taylor, 25, Sandown Close, Bagby, Thirsk, YO7 2PL
Another item selection procedure based on maximum information at shifted ability level gives good results for both 1PL and 2PL
John the Evangelist, Birtley Lane, DH3 2PL
on Monday 23rd August at 11.
Further information and an application form is available either by sending an SAE to Croft Circuit, West Lane, Dalton On Tees, Darlington, North Yorkshire, DL2 2PL
, by calling 01325 721815 or at www.