2010. december 1., szerda


1 megjegyzés:

  1. With the cooperation of metropolitan and provincial places of work of education, 더온카지노 two grades had been examined in a single school, one in every of two grades. The schools that rejected the survey had been changed with pilot sample schools that were beforehand extracted from the same stratification. Post-stratification and weighting had been utilized to match the distribution of the samples and the populations after the survey.