Yılmaz, Esin Hacettepe University - Department of Educational Measurement and Evaluation, Turkey , Koğar, Hakan Başkent University - Faculty of Education - Department of Elemantary Education, Turkey

The Effects of Some Statistical Analysis Findings with Using Different Accommodation of Outlier Techniques

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In this study, to get through these outlier problems, some techniques were used for accommodation of outliers such as trimmed mean, winsorized mean and truncation. The data for this study were gathered from the freshmen and senior students studying classroom teacher (548) education at seven universities from seven different regions in 2007-2008 school year. In consequence of using for accommodation of outliers, the mean difference between groups and t values were decreased. These consequences may be generalized to ANOVA findings. Moreover, it was found out that, outliers in data sets effect correlation coefficients significantly. Before using independent samples t test and one-way ANOVA, from accommodation of outliers techniques, truncation must be used. In addition, before using correlation coefficient analysis, trimmed mean must be preferred. For future studies, it can be suggested that the techniques for using accommodation of outliers be researched for psychometric properties of scales.

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Outlier , trimmed mean , winsorized mean , truncation

Başkent University Journal Of Education

67