, Variant control: a student who made a survey of secondary level 1 33 2 secondary class of 33 people and the secondary 3 number of 34 people including all 100 people .
merger variables covered: students who have made a survey of the Mathayom 1 33 interestingly, this year the number of 2 33 years of school education, and the number of 3 34 100 people as well as all people