What is the probability of meeting at least one person with the flu in 12 random encounters on campus when the infection rate is 3% (3 in 100 people have the flu)

Respuesta :

Answer-

The probability of meeting at least one person with the flu in 12 is 0.3062 or 30.62%

Solution-

The probability of k successes in n trials where p is the probability of success on any given trial is given by,

[tex]P(n;k,p)=\binom{n}{k}(p)^k(1-p)^{n-k}[/tex]

Here, 3 people out of 100 have the flu, so

[tex]p=0.03[/tex]

As there are total 12 number of people, so

[tex]n=12[/tex]

And

[tex]P(\text{At least one flu})=1-P(\text{0 flu})[/tex]

The probability selecting 0 number of person with the flu out of 12 is,

[tex]=\binom{12}{0}(0.03)^0(1-0.03)^{12-0}[/tex]

[tex]=1\times 1\times(0.97)^{12}[/tex]

[tex]=0.6938[/tex]

So, the probability of meeting at least one person with the flu in 12 is,

[tex]=1-0.6938[/tex]

[tex]=0.3062[/tex]

[tex]=30.62\%[/tex]