Mike D. answered • 05/03/21
Effective, patient, empathic, math and science tutor
I assume you need to find the mean number of male parents, assuming you select the committee randomly.
There are 9 parents so we can choose the committee in C (9,5) ways = 126 ways
0 male parents. C (6,5) ways as we choose 5 females out of 6 = 6 ways.
1 male parent C (3,1) x C (6,4) as we choose one male out of 3, and 4 females out of 6 = 3 x 15 = 45
2 male parents C (3,2) X C (6,3) = 3 x 20 = 60
3 male parents C( 3,3) x C (6,2) = 1 x 15 = 15
So number of male parents (x) Probability Number x probability
0 6/126 0x 6 /126
1 45/126 1 x 45/126
2 60/126 2 x 60/126
3 15/126 3 x 15/126
To find the mean number (expected number) add up the numbers in the last column giving
(1 x 45 + 2 x 60 + 3 x 15) / 126 = 210 / 126 = 1.67
Mike D.
X = 0, 1, 2, 3 as these are the possible values f the number of male parents05/08/21
Mike D.
For this second problem. X can be 0, 1, 2, 3. There are C (9,3) ways to pick the attractions. X = 0. C (6,3) ways. X = 1. C(3,1) x C (6,2) ways X = 2. C (3,2) x C (6,1) ways. X = 3 C(3,3) x C (6,0) ways. To find the variance on a TI-84 enter 0, 1, 2, 3 in list 1 and the number of ways for each X in list 2. Then use stat tests 1 (list = list 1, freqlist = list 2)05/08/21
Shin U.
Hi sir may i ask what gonna be the X of this, is it 0,1,2,3 or 1,2,3 only? here's the question problem. 1. The student council planned to have a Field trip. They're considering 3 attractions in Manila, 2 attractions in bulacan, and 4 attractions in laguna. If they are to choose 3 attractions to go to, determine the variance of the random variable representing the manila attraction.05/08/21