Answer:
D. 45 sixth graders, 35 seventh graders, 20 eighth graders
Step-by-step explanation:
The question is missing the list of option. The option is:
A. 45 sixth graders, 45 seventh graders, 45 eighth graders
B. 20 sixth graders, 35 seventh graders, 45 eighth graders
C. 20 sixth graders, 20 seventh graders, 20 eighth graders
D. 45 sixth graders, 35 seventh graders, 20 eighth graders
If the librarian wants to survey a group that can represent the true data of the population, choosing the same number for each grade will not represent the population. The number of the sample should be spread similarly to the number of students each grade.
The ratio of students for 6th grade: 7th grade: 8th grade is 220: 170: 100. The 6th grade has highest number of students, followed by 7th grade and then 8th grade the lowest.
The answer that follow 220 : 170 : 100 ratio is option D. The sample size is roughly 20% of the population of each grade
