Statistical analysis Qualitative variables are described considering the absolute and relative frequencies, as quantitative variables are expressed by central position and dispersion measurements. The comparison between the study groups will be performed using the linear regression model of mixed effects; the model residue analysis will be representing through normal graphics. Cohen measure will be used as the size measure, which is expressed by the difference between the mean divided by the standard deviation. The Statistical Analysis System (SAS) will be used for data analysis.