Answer:
The standard error of the proportion is 0.112.
Step-by-step explanation:
The standard error of a proportion is given by the following formula:

In which p is the probability of a success and n is the length of the sample.
In this problem
A success is a student defining themselves regular dietary supplement users. Our of 3000 students, 1500 do. So
.
We take a sample of 20 of them, so
.
So

The answer to 1 4/5 x 2 1/3 would be 4 1/5. Which is greater than 2 1/3.
-1, -8
0, -9
1, -10
2, -11
Hope that helps!