Respuesta :
Answer:
For each person, there are only two possible outcomes. Either they are left handed, or they are not. The probability of a person being left-handed is independent from other people. So we use the binomial probability distribution to solve this question.
0.1% probability that they are all left-handed.
Step-by-step explanation:
For each person, there are only two possible outcomes. Either they are left handed, or they are not. The probability of a person being left-handed is independent from other people. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.
[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]
And p is the probability of X happening.
10% of us are left handed.
This means that [tex]p = 0.1[/tex]
If three people are randomly selected, find the probability that they are all left-handed.
This is P(X = 3) when n = 3. So
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 3) = C_{3,3}.(0.1)^{3}.(0.9)^{0} = 0.001[/tex]
0.1% probability that they are all left-handed.
