SOLUTION: I have tried solving this type of question multiple times, I am not sure if I am missing a step somewhere. The question is: A insurance fraud inspector is going to audit 7 peopl

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Question 916586: I have tried solving this type of question multiple times, I am not sure if I am missing a step somewhere. The question is:
A insurance fraud inspector is going to audit 7 people from a pool of 18 people. How many different combinations are there?
I'm pretty sure you would use the formula 18!/ 7!(18-7)! however, my calculator does not have n! or any others to work these formulas so I am having to plug everything in on my own in my calculator. Have read thoroughly through my book and professor provided no lecture for this unit. In desperate need of explaining. I know that when the order doesn't matter, but you don't have the same total you would do 18*17*16....etc. Not sure what I'm doing wrong.
Answer by ewatrrr(24785) (Show Source):
You can put this solution on YOUR website!
Yes, 18C7 = 18!/ 7!(18-7)! == 31824 Using Calculator
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IF the Order, the 7 choices, are in matters...that's 18P7
18P7 = 18!/(18-7)! = 18!/11! = = 160,392,960 (child's play on a calculator
These concepts has nothing to do with the order You multiply = for ex
If You can use a calculator in class/testing... You must have one with a reasonable capability.
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Time is of an essence...in homework as well as testing.
Factorial capability (n!) is a minimum (and my guess would be any $12 calculator would have that n! button)
albeit it pricey, the TI83 or later is very popular for statistic students,
albeit it takes time to learn how to use it to its max.