Assessment in education employing web tools, also known as e-assessment, deals with the effective use of technology to support successful instruction. The aim of this study was to investigate learning outcomes and the students' attitudes to online Moodle quizzes in order to improve instructional design. The research population included 204 college students enrolled in life sciences who were participating in an introductory physics course. A blended learning model was used, based on large, traditional face-to-face lectures, practice sessions held with smaller groups of about 25 students and a rich Moodle learning environment. The students' knowledge and understanding were assessed weekly throughout the semester, using two different methods: three ordinary short written tests and online quizzes in the Moodle environment. The students' attitudes towards the online quizzes as compared to the written tests were investigated by questionnaire. Results indicate that both the average grade on written tests and the average grade on online quizzes were found to be significant predictors of the grade on the final exam. Students significantly improved their scores and greatly shortened their performance time on the last attempts of the online quiz, as compared to their first attempts. The investigation into the students' attitudes towards online quizzes reveals a generally positive attitude. Learning outcomes and the students' attitudes to online Moodle quizzes were considered to improve instructional design, which demonstrates formative assessment in higher education.