PENGARUH STRATEGI PEMBELAJARAN BERBASIS MASALAH DAN MOTIVASI BELAJAR TERHADAP KEMAMPUAN BERPIKIR KRITIS DAN HASIL BELAJAR BIOLOGI SISWA SMAN 1 LUBUK PAKAM

This study aims to know: (1) The influence problem based-learning on students critical thinking skills; (2) The influence problem based-learning on student achievement; (3) The influence students motivation on students critical thinking skills ; (4) The influence students motivation on students student achievement; (5) The interaction between problem based-learning and students motivation on students critical thinking skills; (6) The interaction between problem based-learning and students motivation on student achievement. This was a quasi experiment. The study population was XI Science grade students of SMA Negeri 1 Lubukpakam school year 2010/2011. The sampling technique using cluster random sampling that consists of four classes with 164 students. The research instrument in the form of the motivation questionnaire, critical thinking skills test, and result of learning test. Technique of analyzing data used Anava two way at α 0,05. The results showed that: (1) The average the students critical thinking skills that taught by learning of problem based-learning was higher (28,60) from groups of students that taught by learning conventional (21,05), with range of critical thinking skills test scores of 0-40; (2) The average the students achievement of biology that taught by learning of problem based-learning was higher (28,82) from groups of students that taught by learning conventional (21,77) with range of achievement test scores of 0-35; (3) The average critical thinking skills of students who have high motivation to learn was higher (26,60) from groups of students have low motivation to learn (22,98); (4) The average students achievement of biology that have a high motivation to learn was higher (26,25) from groups of students have low motivation to learn (24.31); (5) There was interaction between problem based-learning and students motivation to students' critical thinking skills. (6) There was interaction between problem based-learning and students motivation to students achievement of biology.