Question

Use the geometric probability distribution to solve the following problem. On the leeward side of the island of Oahu, in a small village, about 74% of the residents are of Hawaiian ancestry. Let n = 1, 2, 3, … represent the number of people you must meet until you encounter the first person of Hawaiian ancestry in the village. (a) Write out a formula for the probability distribution of the random variable n. (Enter a mathematical expression.) P(n) = p(1 - p)n-1 (b) Compute the probabilities that n = 1, n = 2, and n = 3. (For each answer, enter a number. Round your answers to three decimal places.) P(1) = 0.740 P(2) = 0.192 P(3) = 0.050 (c) Compute the probability that n ≥ 4. Hint: P(n ≥ 4) = 1 − P(n = 1) − P(n = 2) − P(n = 3). (Enter a number. Round your answer to three decimal places.) 0.018 (d) What is the expected number of residents in the village you must meet before you encounter the first person of Hawaiian ancestry? Hint: Use μ for the geometric distribution and round. (Enter a number. Round your answer to the nearest whole number.) residents

Answer 1

(a)
`\text{P(n)} = \text{p} * \text{(1 - p)}^(n-1) ; \text{ n} = 1, 2, 3,....`

(b) P(1) = 0.740, P(2) = 0.192, and P(3) = 0.050.

(c) The probability that n ≥ 4 is 0.018.

(d) The expected number of residents in the village you must meet before you encounter the first person of Hawaiian ancestry is 3.

Explanation:

We are given that on the leeward side of the island of Oahu, in a small village, about 74% of the residents are of Hawaiian ancestry.

Let n = 1, 2, 3, … represent the number of people you must meet until you encounter the first person of Hawaiian ancestry in the village.

(a) We can observe that the above situation can be represented through the geometric distribution because the geometric distribution states that we will keep on going with the trials until we achieve our first success,

Here also, n represent the number of people you must meet until you encounter the first person of Hawaiian ancestry in the village.

So, the probability distribution of the geometric distribution is given by;

`\text{P(n)} = \text{p} * \text{(1 - p)}^(n-1) ; \text{ n} = 1, 2, 3,....`

where, p = probability that the residents are of Hawaiian ancestry = 74%

(b) The probabilities that n = 1, n = 2, and n = 3 is given by;

`\text{P(n)} = \text{p} * \text{(1 - p)}^(n-1)`

P(1) =
`\text{0.74} * \text{(1 - 0.74)}^(1-1)` = 0.74

P(2) =
`\text{0.74} * \text{(1 - 0.74)}^(2-1)` = 0.192

P(3) =
`\text{0.74} * \text{(1 - 0.74)}^(3-1)` = 0.050

(c) The probability that n ≥ 4 is given by = P(n ≥ 4)

P(n ≥ 4) = 1 - P(n = 1) - P(n = 2) - P(n = 3)

= 1 - 0.74 - 0.192 - 0.050

= 0.018

(d) The expected number of residents in the village you must meet before you encounter the first person of Hawaiian ancestry is given by = E(n)

We know that the mean of the geometric distribution is given by;

Mean =
`(p)/(1-p)` =
`(0.74)/(1-0.74)`

=
`(0.74)/(0.26)` = 2.85 or 3 (approx).