Which of these samples is a valid random sample for the population given?
A.
Alia questions three students from her class to learn about the movie preferences of students in her school.
B.
Miles randomly surveys a group of customers at a coffee shop to understand the coffee consumption habits of 18- to 24-year-old Americans.
C.
Carson interviews students working part-time to gather data on the general spending habits of students.
D.
Lea speaks with the managers at half of the town’s 10 supermarkets, which stock similar items, to find out which breakfast cereal is most popular among the town's residents.

Question

Which of these samples is a valid random sample for the population given?
A. 
Alia questions three students from her class to learn about the movie preferences of students in her school.
B. 
Miles randomly surveys a group of customers at a coffee shop to understand the coffee consumption habits of 18- to 24-year-old Americans.
C. 
Carson interviews students working part-time to gather data on the general spending habits of students.
D. 
Lea speaks with the managers at half of the town’s 10 supermarkets, which stock similar items, to find out which breakfast cereal is most popular among the town's residents.

AngeI · Answer

A seems like it might not be random since she picked the students (not sure)
B isn't valid since he could survey people older than 24 or younger than 18 which may not have good info
C isnt random since he is going for a group of people
D is random and valid since anyone can go to stores and he is going to half of the stores and the manager would have information on what sold best
But I'd go for a or d