In a large population, 70 % of the people have been vaccinated. If 4 people are randomly selected, what is the probability that AT LEAST ONE of them has been vaccinated?

Respuesta :

Answer:

The probability that at least one of the 4 people has been vaccinated is 0.9919.

Step-by-step explanation:

It is given that in a large population, 70 % of the people have been vaccinated. So, the probability of success is

[tex]p=\frac{70}{100}=0.7[/tex]

Probability of failure is

[tex]q=1-p=1-0.7[/tex]

According to binomial distribution.

[tex]P(x=r)=^nC_rp^rq^{n-r}[/tex]

We need to find the probability that at least one of the 4 people has been vaccinated.

[tex]P(x\geq 1)=1-P(x<1)[/tex]

[tex]P(x\geq 1)=1-P(x=1)[/tex]

[tex]P=1-^4C_0(0.7)^0(0.3)^{4-0}[/tex]

[tex]P=1-1(0.0081)[/tex]

[tex]P=0.9919[/tex]

Therefore the probability that at least one of the 4 people has been vaccinated is 0.9919.

Answer: 0.9919

Step-by-step explanation:

Binomial probability formula :-

[tex]P(x)=^nC_xp^x\ (1-p)^{n-x}[/tex], where n is total number of trials , P(x) is the probability of getting success in x trials  and p is the probability of getting success in each trial.

Given : The proportion of the people have been vaccinated: p=0.7

If 4 people are randomly selected, then the probability that at least one of them has been vaccinated will be :-

[tex]P(X\geq1)=1-P(0)[/tex]

[tex]=1-^4^C_0(0.7)^0(0.3)^4\\\\=1-(0.3)^4=0.9919[/tex]

Hence, the probability that at least one of them has been vaccinated =0.9919

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