Reliability: The reliability of multi-item or ordinal scales
was determined by computing Cronbach alphas. The
minimum amount of Cronbach alphas in behavioral
science variables is 0.6. Cronbach alphas after two pretest
stages with 50 respondents were all higher than 0.6.
Thus, we can conclude that the questionnaire is valid and
reliable. To assess the reliability of the questionnaire, the
first pre-test stage was conducted on a small sample of 50
respondents. After obtaining the result, the Cronbach
alpha for altruistic motives was 0.56, but the other
variables had satisfactory values. It seems that the
questions on altruistic motives were vague, so the
questions were revised to be more explicit. The Cronbach
alphas for all variables in the second pre-test stage using
a small sample of 50 respondents were satisfactory.