자료수집은 2019년 3월 14일부터 2019년 3월 28일까지 실시되었으며, 사전에 학교장과 담당교사의 허락을 받았다.
Data collection was conducted from March 14, 2019, to March 28, 2019, and permission was obtained from the principal and the teacher in charge in advance.