Hi; In the simulation studies we need to save some measure in the output as a variable to do some calculation on them, how we can do that? For example: the p-value , t-value, in t-test ( t.test( ) ) or The estimated parameters in some models,(Ex: IRT model: graded response model) in ltm package: (see grm model in attachment file) grm(data, constrained = FALSE, *IRT.param* = TRUE, ...) *IRT.param:* bij: difficulty parameter for item i and category j) ai : discriminant parameter for item i) thata(k) : ability parameter for person k Note that this package does not give theta(k) even in output! How can i load theta parameters? Thanks in advanse -------------- next part -------------- A non-text attachment was scrubbed... Name: GRM.png Type: image/png Size: 6495 bytes Desc: not available URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20141020/66131974/attachment.png>