Question 660952
The answer is highlighted in <font color="red">red</font> below


In an experiment involving a treatment applied to 6 test subjects, researchers plan to use a simple random sample of 6 subjects selected from a pool of 8 available subjects. How many different random samples are possible?
A.210
B.250
<font color="red">C.28</font>
D.7776



Here's why the answer is <font color="red">choice C.</font>



You have 8 choices for the first slot, 7 for the second, 6 for the 3rd, 5 for the 4th, 4 for the 5th, and 3 for the 6th


So if order matters, then you have 8*7*6*5*4*3 = 20,160 different ways to choose 6 people from a pool of 8.


But order doesn't matter, so you have to divide by 6! = 6*5*4*3*2*1 = 720 to get


20160/720 = 28


So there are <font color="red">28</font> random samples.