Massive open online courses (MOOC for short) intend to teach contents online to interested people without limit of attendance. The aim of this work is to explain, share and analyse the course “Cálculo de probabilidades en las pruebas de acceso a la Universidad” offered by some of us at the Jaume I University during the first semester of 2014. We will explain the contents, objectives and self-evaluation procedures of the course. We examine the academic results by using an external source. This is because a significant proportion of our students were attending the last level of secondary education and we compare the obtained results at the university entrance exam with respect to students who missed out this course. In addition, an anonymous questionnaire allowed us to know the degree of satisfaction of the students which will be also analysed in the work. Our aim is to study interactions for searching a pattern of behaviour for subsequent interpretation and valuation. We hope this experience serves to improve further massive open online courses in the field of mathematics.