Validity and Reliability of Developed Mathematics Achievement Test for Senior Secondary Schools Two in Bayelsa State

The study investigated the validity and reliability of mathematics achievement test for senior secondary schools in Bayelsa state. Two (2) research questions directed the study. The study embraced Instrumentation plan. Instrumentation research design was used for the study because the study aimed at new content and procedures for education activities. The study's sample consists of 1026 test takers from both public and private schools. The study's sample was compiled using stratified sampling techniques and simple random sampling techniques which was based on school location. The research instrument was designed by the researcher. The 100 items in the instrument were selected from the Bayelsa State Ministry of Education curriculum in line with WAEC guideline which was guided with table of specification. The test instrument was analyzed using Principle Component Analysis (PCA) and Cronbach’s alpha KR-20 reliability estimate. The study found out among others that the mathematics achievement test (MAT) for SS 2 students in Bayelsa State has both content and construct validity, the MAT for SS 2 students in Bayelsa State has a reliability of 0.99. In line with the findings and conclusions of the study, it was recommended among others that Test item makers in Nigeria should compel the Federal Ministry of Education to ensure examination bodies to use only psychometrically valid and reliable test to assess students’ achievement during external certificate examination to reduce mass failure among students.