Improving students’ critical thinking skills through Remap NHT in biology classroom

This study was the quasi experiment designed to examine the improvement of critical thinking skills of students in biology classroom taught by Remap NHT learning model. The research was pretest-posttest control group design (Fraenkel & Wallen, 2009). There were 25 classes as a population of study, then tested their equity based on the national test scores. Analyses performed used t-test by SPSS 23.0 for Windows. The equity test results showed that there were 10 classes had the equivalence. The two classes were chosen randomly, a class as the control and another one as an experimental class. The control class taught using learning as usual with lectures, discussions, and presentations without designed with a specific learning models. An experimental class taught using Remap NHT.

The research instruments developed by the researchers include the treatment and measurement instruments. Treatment instrument consisted of a syllabus, lesson plans, sets of questions, and worksheets. Students’ critical thinking skills was measured by 18 numbers of written essay tests, and then their answers were scored by rubric critical thinking skills embedded essay test refers to Finken and Ennis (1993) that adapted by Zubaidah, Corebima, and Mistianah (2015). The instrument previously was validated by experts and empirical validation. The validity of the instrument including content and construction validation was done by two senior lecture who have expert in evaluation of biology education at Department of Biology, Faculty of Mathematics and Natural Science, UniversitasNegeri Malang, Indonesia. The content validity was determined by the extent to which the question items representing all subject matter. The construction validity included quality items overall instrument based on a clear definition of operational variables. The construction validity test was done by revised learning instruments based on expert suggestions. The results of the validation from the experts indicated that the instruments was valid.

Empirical validity was conducted by testing those 18 numbers of written essay tests to 50 students from another schools. The test was carried out to determine the validity and reliability of the instrument. Validity refers to the extent of measuring instruments precision and accuracy in the conduct of measurement functions. The validity of an instrument related to the ability to measure the characteristics of the variables. The reliability related to the degree of test scores was free of measurement error or an index that indicates the extent to which a measuring instrument was reliable. The test results showed that the instrument was valid and reliable.

The study carried out for 4 months. At the beginning of learning experiment, students were given a pre-test and at the end given a post-test in the form of 18 numbers of written essay tests. The pre-test and post-test data were scored using a rubric critical thinking skills embedded essay test as described previously, then analyzed using one way ANCOVA. Those data previously was tested by pre requisite test including normality data test using One Sample Kolmogorov-Smirnov and homogeneity test using the Levene’s Test of Equality of Error Variance. Data analysis was done by using SPSS 23.0 for Windows.