This study was conducted in order to establish a base level of information on whether or not Tanzania students are acquiring competence in science process skills as prescribed in the competence based curriculum of 2005. The competence based curriculum of 2005 was designed to reduce teacher-centered instruction in favor of student-centered learning characterized by active learning, solving problems, challenging existing knowledge, and participating in lively discussion, which is thought to be achieved by an inquiry-based approach . Firstly, the study developed and validated a science process skills test specific for Biology (BPST) to be used in assessing students’ competence in this area. In the second stage, the study employed the test that has been developed and validated in the first stage (BPST), to examine the knowledge level of science process skills of advanced level secondary school Biology students in the municipality of Morogoro. Science process skills are one among many competences strongly advocated by the competence based curriculum to learners. In the third stage, the effectiveness of inquiry-based approach on students’ scientific process skills development, conceptual understanding of contents and motivation was investigated. Inquiry-based approach to science has also been heavy emphasized by the new curriculum in Tanzania. Eight (08) weeks genetics lessons were designed for a quasi-experimental intervention from Tanzania Biology syllabus on the basis of both inquiry-based learning principles and conventional style.
Through careful attention to the standards for developing validity arguments of a psychometric test, the study provided comparative validity evidence related to test content, response process, and internal structure. Findings from an analysis of data gathered in the pilot study using the developed test (BPST) involving 610 Morogoro students indicated that the test is reliable and valid enough to be employed in a large scale study. The developed Biology process skills test (BPST) had an internal consistency reliability of 0.80 cronbach alpha, a difficulty index of 0.447 and an overall discrimination index of 0.48. Furthermore the content validity of BPST is 0.88, concurrent validity of 0.51 and a construct validity (discriminant correlation coefficient) of 0.34. The readability level of BPST is 72 (fairly easy). The test may also be a useful means of classroom-based research, evaluation of instruction and learning, curriculum validation, as well as an alternative to authentic methods of assessing scientific skills acquisition.
In the second stage of the study which examined the knowledge level of Morogoro students in the area of science process skills, the validated BPST found that students had a barely average knowledge level of the skills. The mean of test scores was 17.2 out of 35 items in the test which is equivalent to 49.1%. Specifically, Morogoro students performed relative better on items measuring their ability in identifying and controlling variables with score mean of 4.05 (57.8%) out of 07 items and they performed extremely poor on items which measured their skills in analyzing and interpreting data with the mean of 2.34 (33.4%) out of 07 items. Due to the influence of social forces, culture and gender roles in the Tanzania, anecdotal evidence would suggest male students to have higher levels of achievement in science-related disciplines than females. However, the findings from Morogoro Biology students in this study did not support that assertion. Based on the science process skills test scores of the 246 females and 107 males in the study, independent samples t-test found a statistical significant difference in favor of female students.
In the third phase, an analysis of BPST posttest scores revealed that the experimental group students performed better in science process skills after undergoing treatments of inquiry constructivist activities as compared to their counterparts in the control group. An analysis of independent samples t-test based on type of instruction students received at (α) =0.05 produced a p of 0.047 and a t value of 0.633, hence rejecting the null hypothesis (Ho1). However repeated measures ANOVA found that regardless of the method of teaching, there were significant within-groups effects with regard to the development of science process skills. The same results were also obtained with respect to achievement in genetics and motivation. On the other hand, students’ scientific skills did not correlate with variables of motivation and genetics. However, generalization of these findings is not possible because of the nature of the study and the sample size used in each stage. It is therefore suggested that replication of the similar study in alternative educational settings is needed before generalization.