- #1
perplexabot
Gold Member
- 329
- 5
Hello all. This is NOT homework. Here is the question:
Approximately 10% of the population is left-handed. In a classroom of 7 people, find the probability that at least one person is left handed. Assume independence.
a) 0.1000
b) 0.0823
c) 0.9176
d) 0.7000
Here is my approach to the question:
Let LH: left handed
and RH: right handed
P(at least 1 LH) = P(not all RH)
P(not all RH) = 1 - P(all RH)
P(all RH) = (1 - .1)^7 = .9^7
P(not all RH) = 1 - .9^7
P(at least 1 LH) = 1 - .9^7 = .5217
As can be seen, my answer is not one of the options shown above. I have been trying to do this question for a while now and have reached the point of frustration. May someone please help?
Note: Does my problem have to do with the fact that LH and RH are not mutually exclusive? In other words someone may be LH and RH?
Thank you!
Approximately 10% of the population is left-handed. In a classroom of 7 people, find the probability that at least one person is left handed. Assume independence.
a) 0.1000
b) 0.0823
c) 0.9176
d) 0.7000
Here is my approach to the question:
Let LH: left handed
and RH: right handed
P(at least 1 LH) = P(not all RH)
P(not all RH) = 1 - P(all RH)
P(all RH) = (1 - .1)^7 = .9^7
P(not all RH) = 1 - .9^7
P(at least 1 LH) = 1 - .9^7 = .5217
As can be seen, my answer is not one of the options shown above. I have been trying to do this question for a while now and have reached the point of frustration. May someone please help?
Note: Does my problem have to do with the fact that LH and RH are not mutually exclusive? In other words someone may be LH and RH?
Thank you!