Given that this was a quasi-experimental design, to achieve greater internal validity to groups were randomly selected from five natural groups that were already comprised in branches of the metropolitan area, through raffle, and "pre-test-post-test design and control group" were used; selection of the intervention group and control group were also carried out randomly.
Por tratarse de un diseño cuasiexperimental, para lograr mayor validez interna, los grupos se eligieron aleatoriamente de cinco grupos naturales que ya se encontraban conformados en sedes del área metropolitana, a través de tómbola, y se utilizó un ''diseño con preprueba–posprueba y grupo control".