How does late-night screen time affect cognitive flexibility in adolescents? Are there significant differences in susceptibility to sleep disruption between early adolescents (aged 11–12) and mid-adolescents (aged 14–15)? To investigate this, cognitive psychologists plan to conduct a study using computerized executive function testing and digital sleep-log diaries. The researchers decide to select a stratified sample of 80 participants from two different local secondary schools, ensuring equal representation of year groups (Year 7 and Year 10) and genders.
Justify the choice of this sample for this investigation.
