suppose you have to survey 70 students in a school. there are 230 grade 9s, 215 grade 10s, 195 grade 11, 190 grade 12s, how many students should you survey from each grade so that the numbers are proportional to the number of students in each grade?
+122 Find total
230+215+195+190= 830 students.
Next you divide the numbers from each grade with the total for the school to find the proportions for each grade.
I.e.
Grade 9 = 230/830=0.277
Grade 10=215/830=0.259
Grade 11=195/830= 0.235
Grade 12=190/830=0.229
The just multiply each result with the number you're surveying (70*0.277= 19.39 to survey from grade 9).
Then you end up with;
19 from grade 9
18 from grade 10
17 from grade 11
16 from grade 12
+122 Find total
230+215+195+190= 830 students.
Next you divide the numbers from each grade with the total for the school to find the proportions for each grade.
I.e.
Grade 9 = 230/830=0.277
Grade 10=215/830=0.259
Grade 11=195/830= 0.235
Grade 12=190/830=0.229
The just multiply each result with the number you're surveying (70*0.277= 19.39 to survey from grade 9).
Then you end up with;
19 from grade 9
18 from grade 10
17 from grade 11
16 from grade 12
