00:01
Okay, here we're going to use the formula for ncr that you can find on all formula sheets.
00:06
It's n factorial, n minus r factorial, r factorial.
00:14
Now, i want to work out a sample space first.
00:17
I'm going to choose a 12 -person jewelry.
00:19
If i don't care who's on it, my choice is 27 people, 14 men, 13 women.
00:26
So what i have is 27 to choose from.
00:29
So 27 choose 12 and that i can work out on the ti 84 plus calculator just or either do this plug it into the formula and we get here 15 factorial 12 factorial and work that out on a calculator or easier still press the math button on the ti 84 plus with the arrow key go across to pr ob the fourth one over then go down to ncr and just type in 27c12 upway next chance of error so it's one seven three eight three eight six oh so there are 17 .4 million ways of choosing a 12 -person jewelry from 27 people but what i want is all men well there are 14 men which means 14 to choose from so 14 choose 12.
01:39
Again, that's 14 factorial over 2 factorial, 12 factorial.
01:45
And that i could do manually...