Question 1150898: Given the population of elements (22,24,26)
Write down all possible samples of size two chosen by simple random sampling
Answer by jim_thompson5910(35256)   (Show Source):
You can put this solution on YOUR website!
We have n = 3 items to form groups of r = 2.
We can use the nCr formula to get
nCr = (n!)/(r!*(n-r)!)
3C2 = (3!)/(2!*(3-2)!)
3C2 = (3!)/(2!*1!)
3C2 = (3*2*1)/(2*1*1)
3C2 = 6/2
3C2 = 3
There are 3 groups we can form
{22,24}
{22,26}
{24,26}
You can think of it as "there are 3 ways to not pick an item". Or put another way "there are 3 ways to pick an item that we will erase" (whatever isnt erased is in the two item set).
The order does not matter within any given set. Something like {22,24} is the same as {24,22}. It's often handy to list the values from smallest to largest just so things stay consistent.
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