A middle school has… 220 students in the 6th grade; 170 students in the 7th grade; and 100 students in the 8th The librarian wants to know which books are the most popular among the students in her school. Since she cannot ask all the students, she will survey a group of them. Part A: Which sample can best help her to draw conclusions about the preferences of all the students in the school? Group of answer choices

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

x is variable or an unknown value to find

example:

2x = 5 which means x = 3

one that is bigger than 3 1/2