asked 18.1k views
1 vote
Please help!!

You and your colleagues have randomly chosen 15 children from the city schools to pilot
your new science program starting this January.
An irate parent (in an editorial to the local newspaper) claims you are favoring males in
your selection. Your random sample has 9 males and 6 females. (The entire population
of children this age in your community, from which you have chosen your sample, is
70% male and 30% female.)

How likely is it to draw a sample of 15 with 6 or fewer females from this
population? (Please show all of your work and setup.)

1 Answer

4 votes

Answer:The probability calculated will give you the likelihood of drawing a sample of 15 with 6 or fewer females from the given population.

Step-by-step explanation:To determine the likelihood of drawing a sample of 15 with 6 or fewer females from a population where 70% are male and 30% are female, you can use the binomial probability formula. In this case, you want to calculate the probability of getting 6 or fewer females out of 15.

The binomial probability formula is:

\[P(X = k) = C(n, k) * p^k * (1 - p)^(n - k)\]

Where:

- \(P(X = k)\) is the probability of getting exactly k successes.

- \(C(n, k)\) is the binomial coefficient, which represents the number of ways to choose k items from n items.

- \(p\) is the probability of success (probability of selecting a female).

- \(n\) is the total number of trials (sample size).

In this case, we want to calculate the probability of getting 6 or fewer females, so we need to calculate the probabilities for k = 0, 1, 2, 3, 4, 5, and 6 females and then sum them up.

Given that the population is 70% male and 30% female, \(p = 0.30\), and \(n = 15\).

Let's calculate the probabilities:

For k = 0 (0 females):

\[P(X = 0) = C(15, 0) * (0.30)^0 * (1 - 0.30)^(15 - 0) = 1 * 1 * 0.7^15\]

For k = 1 (1 female):

\[P(X = 1) = C(15, 1) * (0.30)^1 * (1 - 0.30)^(15 - 1) = 15 * 0.30 * 0.7^14\]

Continue this process for k = 2, 3, 4, 5, and 6, and sum up the probabilities:

\[P(X ≤ 6) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) + P(X = 6)\]

Calculate each term and sum them up to find the total probability. You can use a calculator or statistical software to perform these calculations.

The probability calculated will give you the likelihood of drawing a sample of 15 with 6 or fewer females from the given population.

answered
User Borislemke
by
7.8k points
Welcome to Qamnty — a place to ask, share, and grow together. Join our community and get real answers from real people.