Answer:
d.a cluster sampling
Step-by-step explanation:
This plan exemplifies Cluster sampling. It is a sampling method where populations are placed into different separate groups like here into freshman, sophomore, junior, and senior classes. A random sample of these groups is then selected as here thirty students selected from each group to represent a specific population.<u> It is usually used in that type of research when there is no possible way to find information about a population as a whole.</u>
1x+1x+2x=180
4x=180
x=45
45:45:90
Hope this helps!
A 4/52
B 26/52
C 13/52 of course in simpilest form though.
Answer: A
Step-by-step explanation: