Question 212010
Two balls are to be selected without replacement from a bag containing one red, one blue, one green, and one yellow ball. How many points are there in the sample space?
<pre><font size = 4 color = "indigo"><b>
4 choose 2

{{{4C2=(4!)/(2!2!)=(4*3*2*1)/((2*1)(2*1))=6}}}

The 6 points in the sample space are these 6 
subsets, each containing 2 elements:  

1. {red, blue}
2. {red, green}
3. {red, yellow} 
4. {blue, green} 
5. {blue, yellow}
6. {green, yellow}

Edwin</pre>