Önder Sünbül

Effects of Test Level Discrimination and Difficulty on Answer-Copying Indices.

Received Nov 19, 2017 Revised Jan 27, 2018 Accepted Feb 14, 2018 In this study Type I Error and the power rates of omega (ω) and GBT (generalized binomial test) indices were investigated for several nominal alpha levels and for 40 and 80-item test lengths with 10,000-examinee sample size under several test level restrictions. As a result, Type I error rates of both indices were found to be below the acceptable nominal alpha levels. The power study showed that average test difficulty was very effective for power (true detection) rates of indices. Clear patterns were observed for the increase of test difficulty in favor of both ω and GBT power rate. Contrary to expectations; average test discrimination was not as effective as average test difficulty. The results of the interaction effects of item discrimination and difficulty showed that for the cases whose b parameters were lower than 0 with weak discrimination, indices had weak power for both ω and GBT. In addition, for the cases whose b parameter levels were below zero with high discrimination indices, the power performance of both answer-copying indices were very weak. Results for test length showed that with the increase of test length the power rate of both ω and GBT tended to increase. Also, ω performed slightly better than GBT or very close to GBT for 80-item test length however, ω performed better than GBT in terms of power rate for the cases with 40-item test length. Keyword:

The Validity and Reliability Study of Turkish Version of Work-Related Flow Inventory (WOLF)

This study aims at determining the reliability and validity of the work-related flow inventory (WOLF). WOLF was developed by Bakker in 2008 and contains 13 items with three dimensions (absorption [4 items], enjoyment [4 items], and intrinsic work motivation [5 items]). This inventory was originally conducted over seven employees who work at companies in the Netherlands. Yalcinkaya translated WOLF into Turkish and conducted the validity and reliability of the inventory, but according to her study’s results, she had reduced 13 items to 12 and three dimensions to two. In our study, Bakker first provided a letter of permission, after which the inventory was translated into Turkish by a specialist. The Turkish version of WOLF was conducted over 40 health employees working at a university hospital in Edirne. Three weeks later, measures were performed again; we examined the WOLF inventory as performed by Bakker in 2008, and completely validated 13 items and three dimensions. The Turkish version of WOLF can be used in research to determine the effects of work-related flow on the workforce in health services.

Madde Parametrelerininin Değişmezliğinin Çeşitli Boyutluluk Özelliği Gösteren Yapılarda Madde Tepki Kuramınana Göre İncelenmesi

Bu calismada, cesitli boyutluluk ozelliklerine sahip yapilardaki madde parametrelerinin degismezligi MTK cercevesinde incelenmistir. Bu amac dogrultusunda, tamamlayici cok boyutlu madde tepki kurami modeline dayali iki boyutlu veri uretimi yapilmistir. Veri uretiminde, birinci boyut maddelerinin sayisi (24) ve a1 parametre ortalamasi (1.00), butun yapilarda ayni olacak sekilde korunmustur. Degisimlemeler, ikinci boyutta yer alan maddeler uzerinde ve boyutlar arasi korelasyonlarda yapilmistir. Ikinci boyut maddelerinin sayisi 4, 8, 12, 16, 20, 24; a2 parametre ortalamasi 0.25, 0.50, 0.75,1.00 ve boyutlar arasi korelasyon 0.00, 0.30, 0.60, 0.80 olacak sekilde degisimlenmistir. Degisimleme olcutlerinin tamaminin caprazlanmasi sonucu, 96 deneysel hucre elde edilmistir ve herbir hucre icin 90.000 bireyin madde tepkisini kapsayan veri uretimi yapilmistir. Boylelikle 96 adet evren elde edilmistir. Parametre degismezliginin orneklem buyuklugunden nasil etkilendigini belirlemek amaciyla, her evrenden 500’luk 100 adet, 1000’lik 100 adet ve 3000’lik 100 adet orneklem, basit seckisiz ornekleme yontemine dayali olarak cekilmistir. Boylelikle 28 800(96 x 3 x 100) orneklem elde edilmistir. Elde edilen orneklemler MTK cercevesinde analiz edilmistir. Elde edilen analiz sonuclarinin degerlendirilmesinde, parametre degismezliginin gostergesi olarak standart hata ortalamalarindan yararlanilmistir. Veriler boyutlara gore gruplanmadan analiz edilse de, standart hata ortalamalari her boyut icin ayri ayri hesaplanarak, her iki boyutun parametre degismezliginden nasil etkilendigi belirlenmistir. MTK icin elde edilen sonuclar incelendiginde, hem a hem de b parametresi icin parametre degismezliginin buyuk oranda saglandigi gorulmekle beraber bazi yapilarda parametre degismezliginin saglanamadigi gorulmustur. Bu yapilar; ikinci boyutun birinci boyuta kuvvetce esdeger (madde sayisi ve a parametre ortalamasi) ve boyutlarin birbirine dik konumlandigi deneysel hucrelerdir. Belirtilen deneysel hucreler icin hesaplanan standart hata ortalamalarinin, ozellikle b parametresi icin, kabul edilemeyecek kadar buyuk oldugu gorulmustur. Belirtilen ozel durumlar haricindeki deneysel hucrelerde; MTK tekboyutluluk sayiltisinin ihlal edilmesine ragmen, degismez madde parametreleri uretebilmistir. Literaturde de belirtildigi uzere, MTK’nin cokboyutluluga karsi oldukca dayanikli oldugu gorulmustur.