Respuesta :
Using the binomial distribution, there is a 0.265 = 26.5% probability that at least two of them have the same number.
What is the binomial distribution formula?
The formula is:
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]
The parameters are:
- x is the number of successes.
- n is the number of trials.
- p is the probability of a success on a single trial.
For this problem, the values of the parameters are:
p = 1/65 = 0.0154, n = 65.
The probability that at least two of them have the same number is:
[tex]P(X \geq 2) = 1 - P(X < 2)[/tex]
In which:
P(X < 2) = P(X = 0) + P(X = 1)
Then:
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 0) = C_{65,0}.(0.0154)^{0}.(0.9846)^{65} = 0.3647[/tex]
[tex]P(X = 1) = C_{65,1}.(0.0154)^{1}.(0.9846)^{64} = 0.3703[/tex]
So:
P(X < 2) = P(X = 0) + P(X = 1) = 0.3647 + 0.3703 = 0.735.
[tex]P(X \geq 2) = 1 - P(X < 2) = 1 - 0.735 = 0.265[/tex]
0.265 = 26.5% probability that at least two of them have the same number.
More can be learned about the binomial distribution at https://brainly.com/question/24863377
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