Problem-based learning to develop students’ character in biology classroom

The design of this research was a quasi-experimental design to compare the influence of PBL teaching strategy and direct instruction (traditional strategy) on the development of student character. In PBL class students were taught followed the PBL syntax: problem orientation, organizing students to learn, lecturer guiding students to do the inquiry, develop and present the work, and analyse and evaluate the problem solving process (Arends, 2008). In traditional learning, students were taught with the lecturer-centred, where lecturer teach with dominated by direct instruction.

The design of the research was pre-test-post-test control group design (Fraenkel & Wallen, 2009) (Table 1). The independent variable was teaching strategies consisting of the PBL and the traditional teaching strategy. The dependent variable was students’ characters. This research was conducted for one semester in the first semester of academic year 2019/2020.

Table 1. The quasi-experimental research design

Pre-test	Group	Post-test
O1	X1	O2
O1	X2	O2

X1 = PBL; X2 = Traditional Strategy; O1 = Pre-test scores; O2 = Post-test scores

The population of research consisted of 6 classes of the first year students of Faculty of Mathematics and Natural Science, Indonesia in academic year 2019/2020 as many as 288 students. The sample of research represented all the population. The samples of the study consisted of 72 first year students of Faculty of Mathematics and Natural Sciences, Universitas Negeri Makassar, having equal academic skill based on placement test who were obtained by random sampling. The classes were selected by using simple random sampling technique by the lottery method from the population and entirely by chance because each class has the same probability of being chosen for the sample of research. Two class used in this research employed Basic Biology course. Each teaching strategy was represented by one class. The classes used as the research samples were initially tested for the equality using the data of placement test. The analysis of the equality test used analysis of variance (ANOVA) using SPSS 22.0 for Windows. The result of this analysis showed that two classes were equal (p > 0.05).

The placement test is in the form of multiple-choice tests on the biological materials of senior high school level. The number of the test items was 70 items. Development of student character was measured by using a questionnaire to know students’ early character by using Likert scale. The number of the character questionnaire was 21 items. Besides, development of student character was measured by using observation sheet of character during lab sessions in every meeting. The sample items of questionnaire and observation sheet were measured character covered honesty, discipline, responsibility, creativeness, and care. The placement test, character questionnaire, and behavioral observation sheet were developed by the researcher and were validated before being used. The instruments used were initially validated by experts and by empirical validation. The expert validation covered the content validity and construct validity. The results of the validation from the experts showed that the result was 3.80 (strongly valid for the placement test, 3.69 (strongly valid) for character questionnaire and behavioral observation sheet.

The empirical validation covered validity item test and reliability item test. The empirical validation was conducted on 50 students of second year of Faculty of Mathematics and Science. The item validity test means that an item is said to be valid if it has a great contribution toward the total score. A reliability of a test is associated with consistency. A test is said to have a high reliability if the test can provide consistent results. The results of the empirical validation showed that the validity of placement test was in the range 0.385-0.800 (valid), and the reliability of the placement test was 0.978 (high reliability) meaning that the test had good quality. The results of the empirical validation showed that the validity of character questionnaire was in the range 0.466-0.817 (valid), and the reliability of the character questionnaire was 0.933 (high reliability) meaning that the test had good quality. During one semester, both classes were taught using treatment of different teaching strategy, and then a character questionnaire was given to them by the end of research.

The data of this research were the score of character development of the students on the character questionnaire and character observation sheet. The data from the questionnaire were collected from the pre-test and post-test. The data were then analyzed by using Analysis of Covariance (ANCOVA), which were previously performed in the prerequisite tests namely, the normality test using one-sample Kolmogorov-Smirnov test and homogeneity test using Levene’s Test of Equality of Error Variances. The data were analyzed using SPSS 22.0 for Windows. The data from the behavioural observation sheet were analyzed by using descriptive statistics analysis.