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Scales are evaluated for reliability through two tools is Cronbach coefficient Alpha and factor analysis. Cronbach's Alpha coefficient was used to type the "junk", the variables have the corrected item total correlation is under 0.3 will be eliminated and the scale will be chosen when the Cronbach Alpha coefficient greater than 0.6 (Nunnally & Bernstein, 1994).Reliability is used to describe the degree of measurement error, because we can not know exactly the degree of variability of the correct variables and variable error, cannot be directly the level of reliability of the scales. However, we can establish the credibility based on coefficient of Cronbach Alpha. This factor indicates the degree of correlation between the variable in the questionnaire, which is used to calculate the change of each variable and correlations between variables (Bob e. Hays, 1983).

Scale reliability was assessed through two tools that Cronbach alpha coefficient and factor analysis. Cronbach Alpha coefficients were used to kind of turn "junk", the item total correlation variable sửa less than 0.3 will be disqualified and the scale will be chosen when the Cronbach alpha coefficient greater than 0.6 (Nunnally & Bernstein, 1994).
Reliability is used to describe the degree of measurement error, because we can not know exactly the extent of variation of the variable correctly and turn error, can not be calculated directly at the reliability of the scale. However, we can establish the reliability based on Cronbach Alpha coefficients. This coefficient indicates the degree of correlation between the variables in the questionnaire, was used to calculate the change in each variables and relationships between variables (Bob E.Hays, 1983).