Previous misconceptions about science may cause difficulties in the interpretation of scientific models. A Likert scale test was made and presented to part of the population in order to find out beliefs about science and technology that students who wanted to have a degree in engineering at Universidad Nacional de La Matanza had. Principal components analysis was performed to identify the testees' profile. We show the results referring to the beliefs and conceptions about probability, margin for error, accuracy, certainty, truth and validity. Although most of the people who answered the survey acknowledged the presence of probability in the results of a physical experiment, they also gave it accuracy and truth values which are not inherent. It is also remarkable that only a very low percentage has a posture that is coherent with the scientific vision of the terms.