This skill explains the meaning of "N choose M" notation in probability, which is used to determine the number of ways to choose M items from a group of N items without regard to the order of selection. The formula involves dividing factorials of the total items by the factorial of the selected items and the factorial of the difference between the two.
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Meaning of N choose M notation
Test your understanding of nCm notation by practicing it! Work through the below exercises to use it in practice.
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What does this probability notation of a number, the letter 'C', and another number mean?
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It is said 6 choose 2 when you read it out loud
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What that means is the number of ways you can pick any 2 items from a group of 6 items
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But, and this is quite important, order does not matter. So picking the 3 of clubs and the 7 of hearts is the same as picking the 7 of hearts and the 3 of clubs.
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The equation for it is 6 factorial, divided by 2 factorial times 6 minus 2, or 4, factorial
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Which would calculate out to a value of 15. So there are 15 unique ways to pick 2 cards out of this hand of 6.