Respuesta :
Answer:
(a) The probability mass function of X is:
[tex]P(X=x)={4\choose x}\ (0.33)^{x}\ (1-0.33)^{4-x};\ x=0,1,2,3...[/tex]
(b) The most likely value for X is 1.32.
(c) The probability that at least two of the four selected have earthquake insurance is 0.4015.
Step-by-step explanation:
The random variable X is defined as the number among the four homeowners who have earthquake insurance.
The probability that a homeowner has earthquake insurance is, p = 0.33.
The random sample of homeowners selected is, n = 4.
The event of a homeowner having an earthquake insurance is independent of the other three homeowners.
(a)
All the statements above clearly indicate that the random variable X follows a Binomial distribution with parameters n = 4 and p = 0.33.
The probability mass function of X is:
[tex]P(X=x)={4\choose x}\ (0.33)^{x}\ (1-0.33)^{4-x};\ x=0,1,2,3...[/tex]
(b)
The most likely value of a random variable is the expected value.
The expected value of a Binomial random variable is:
[tex]E(X)=np[/tex]
Compute the expected value of X as follows:
[tex]E(X)=np[/tex]
[tex]=4\times 0.33\\=1.32[/tex]
Thus, the most likely value for X is 1.32.
(c)
Compute the probability that at least two of the four selected have earthquake insurance as follows:
P (X ≥ 2) = 1 - P (X < 2)
= 1 - P (X = 0) - P (X = 1)
[tex]=1-{4\choose 0}\ (0.33)^{0}\ (1-0.33)^{4-0}-{4\choose 1}\ (0.33)^{1}\ (1-0.33)^{4-1}\\\\=1-0.20151121-0.39700716\\\\=0.40148163\\\\\approx 0.4015[/tex]
Thus, the probability that at least two of the four selected have earthquake insurance is 0.4015.
