If there is a group of 35 people out of a total of 118 people, and one of the 118 people is chosen, what is the probability that the chosen person will be part of the group of 35?
I thought that it would be: 35/118 * 1/35 = 0.008613
This probability seems very low to me. And when I try to find the probability that the chosen person IS NOT part of the group of 35, I get a low probability as well (0.008436). I would expect that the two numbers should add to one, which they clearly don't. Any guidance would be greatly appreciated! Thank-you.
2007-06-19 13:48:33 · 3 answers · asked by Kinger 2 in Science & Mathematics ➔ Mathematics
Why did you multiply by the extra 1/35?
There are 35 ways for the selected person to be in the group and 118 ways of selecting 1 person. That makes the probability 35/118 = 29.66%
The probability that the person is not part of the 35-person group is 1-29.66% = 70.34% If you double check, if 35 people of the 118 are in the group then 118-35 = 83 people are not in the group. So then the chance of picking someone not in the group is 83/118 = 70.34%
2007-06-19 14:06:28 · answer #1 · answered by Astral Walker 7 · 1⤊ 0⤋
The probability that a person will be one of the special 35 people is simply 35/118. The probability that they are not part of the special 35 is simply (118 - 35) / 118. Notice these add to one.
2007-06-19 13:58:05 · answer #2 · answered by lithiumdeuteride 7 · 0⤊ 0⤋
the probability for being one of the 35 is 1/35 and 35/118 is the probability of being in 118 people. then add the number together you should get about 0.3 then if it is not part of the group of people:
(118-35)/118=0.7
this add up to one, but I am not sure if it is right.
2007-06-19 13:56:45 · answer #3 · answered by (^_^) CHiccaaqui(^_^) 4 · 0⤊ 0⤋