Answer: a= 14 , b= 15, c =15 , d =18 , e= 18.
Step-by-step explanation:
Stratified sample is a sampling technique used to show the participation of each group present in the population..
Person sampled from each group =[tex]\dfrac{Person\ in\ group}{Population}\times sample\ size[/tex]
Total students = 140+150+150+180+180 =800
In sample
Person of Year 7 students = [tex]\dfrac{140}{800}\times80=14[/tex]
Person of Year 8 students = [tex]\dfrac{150}{800}\times80=15[/tex]
Person of Year 9 students = [tex]\dfrac{150}{800}\times80=15[/tex]
Person of Year 10 students = [tex]\dfrac{180}{800}\times80=18[/tex]
Person of Year 11 students = [tex]\dfrac{180}{800}\times80=18[/tex]
Hence, a= 14 , b= 15, c =15 , d =18 , e= 18.
