Abstract

This research paper presents an analysis of the validity of a constructed Coursebook in Statistics and Probability designed for Grade XI students. The Coursebook incorporates examples, illustrations, and exercises that are contextualized around the products, culture, events, and issues of the Ilocos Region. Research and development methods were employed during the construction process of the Coursebook. To evaluate its effectiveness, the Coursebook was assessed based on Content, Format, Presentation and Organization, Accuracy, and Up-to-datedness. The evaluation revealed that the Coursebook excelled in all areas, receiving a general descriptive rating of Very Satisfactory.In addition to the overall assessment, the readability of the material was analyzed using the Flesch Reading Ease score. The score obtained was 66.88, indicating a Standard/Average level of readability. This suggests that the material can be easily comprehended by eighth and ninthgrade students. This finding is further supported by indicators such as the Gunning Fog Index, Smog Index, Coleman Liau Index, Flesch Kincaid Grade Level, and Automated Readability Index, all of which suggest that the material is accessible to students in Grades six and seven the positive evaluation results and the appropriate readability level, it is highly recommended that the Coursebook in Statistics and Probability be utilized as a reference for both teachers and students in schools. The contextualization of the examples and exercises within the Ilocos Region products, culture, events, and issues not only enhances students' understanding of statistics and probability but also fosters a connection between the subject matter and their local environment. By incorporating this Coursebook into the curriculum, educators can effectively engage students in the learning process while promoting an appreciation for their regional context.