Answer:
a) cluster sampling
Step-by-step explanation:
In cluster sampling method, each member of a population is assigned to one and only one group.This means clusters are formed through probability method usually a simple random sampling.The participants in the clusters are the only one to be surveyed.
In this example, simple random sampling is used to identify 12 home rooms(cluster) where a group of 20 students (participants) in each room is given the survey.
Answer:
43
Step-by-step explanation:
To find the number of days, divide the total swam by the average:
Days = 48 / 3.2 = 15
They swam for 15 days.
