At our residential activity centres in England, Wales, and Scotland, we provide school groups with an introduction to outdoor pursuits, with each session lasting one and a half hours, beginning with an interactive safety talk and a detailed guide through the equipment. The skill of our instructo...
Second, the inclusion of foreigners and sampling from a medical school means that our sample was very specific and not representative of the general population of Plovdiv of that age range. Still, this lack of external validity does not have an effect on the internal validity of our study, ...