¿Cómo los investigadores a determinar lo que es verdad en base a los datos que recogen? Esta pregunta es una de las preocupaciones centrales de estadísticas, que utiliza modelos matemáticos para sacar conclusiones útiles sobre el mundo real.

A certificate is proof of qualification of a certain set of skills. Students who obtain a certificate have completed educational requirements and tests. Through completion, they become ready to pursue a degree or diploma, or to head into the professional world in their field of expertise.