Pre-tests, Two-sample t test, Welch-test, Wilcoxon-U test,

No abstract

SummaryA suggestion is given of how to prove main and interaction effects in two-way layouts independent of each other even if the data are just ordinally scaled. Starting from HILDEBRAND'S (19808, b) non-parametric approach which presupposes interval-scaled data, transformations of ranks are settled before analysis per analogy to the H-test takes place. That is, the same formula of an asymptotically %?-distributed test-statistic results but mean ranks are used instead of mean scores in order to partialize, for instance, maineffects while testing interaction effect. Finally an allusion is given of how to handle ties as well as unequal sample sizes. K e y words:Non parametric test, Two-way layout, interaction.

The linear logistic test model (LLTM) breaks down the item parameter of the Rasch model as a linear combination of some hypothesized elementary parameters. Although the original purpose of applying the LLTM was primarily to generate test items with specified item difficulty, there are still many other potential applications, which may be of use for psychometric research on various testing conditions. This article provides some examples of such applications. The examples include (a) position effect of item presentation (in particular, learning and fatigue effects); (b) content-specific learning effect; (c) effect of speeded item presentation; and (d) effect of item response format.

In aptitude and achievement tests, different response formats are usually used. A fundamental distinction must be made between the class of multiple-choice formats and the constructed response formats. Previous studies have examined the impact of different response formats applying traditional statistical approaches, but these influences can also be studied using methods of item response theory to deal with incomplete data. Response formats can influence item attributes in two ways: different response formats could cause items to measure different latent traits or they could contribute differently to item difficulty. In contrast to previous research, the present study examines the impact of response formats on item attributes of a language awareness test applying different item response theory models. Results indicate that although the language awareness test contains items with different response formats, only one latent trait is measured; no format-specific dimensions were found. Response formats do, however, have a distinct impact on the difficulty of the items. In addition to the effects of the three administered item types, a fourth component that makes items more difficult was identified.