Answer
The cluster sampling method.
Work Step by Step
Using the cluster sampling method:
Let N be the size of the population: N = 1280.
There are 32 sections similar in class size and makeup. So, there are about $\frac{1280}{32}=40$ students per class.
Let n be the sample size: $n=0.10\times1280=128$. But, $\frac{128}{40}=3.2$. So, it is better to randomly select 4 classes (clusters).
This way, we can save time: the students may answer the survey during the algebra class.
Using simple random sampling: we would have to randomly select about 128 students (about 4 per class). It is a more difficult task, although it is not more expensive.
Remenber that cost includes the time required to obtain the sample.
