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Ch. 4 - Probability
Triola - Elementary Statistics 14th Edition
Triola14th EditionElementary StatisticsISBN: 9780137366446Not the one you use?Change textbook
All textbooksTriola 14th EditionCh. 4 - ProbabilityProblem 4.3.8b
Chapter 4, Problem 4.3.8b

Births in Vietnam In Vietnam, the probability of a baby being a boy is 0.526 (based on the data available at this writing). For a family having four children, find the following.


b. The probability that all four children are girls.

Verified step by step guidance
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Step 1: Understand the problem. The probability of a baby being a girl is the complement of the probability of a baby being a boy. Since the probability of a boy is 0.526, the probability of a girl is 1 - 0.526 = 0.474.
Step 2: Recognize that the problem involves a binomial probability distribution. The binomial probability formula is: P(X = k) = (n choose k) * (p^k) * ((1-p)^(n-k)), where n is the number of trials (children), k is the number of successes (girls), and p is the probability of success (girl).
Step 3: For this problem, we are finding the probability that all four children are girls. This means k = 4 (all successes), n = 4 (four children), and p = 0.474 (probability of a girl).
Step 4: Substitute the values into the binomial probability formula. Since k = n = 4, the combination term (n choose k) simplifies to 1. The formula becomes: P(X = 4) = (1) * (0.474^4) * ((1-0.474)^0).
Step 5: Simplify the expression. The term (1-0.474)^0 equals 1, so the probability simplifies to P(X = 4) = 0.474^4. Calculate this value to find the final probability.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Probability

Probability is a measure of the likelihood that a particular event will occur, expressed as a number between 0 and 1. In this context, the probability of a baby being a boy is given as 0.526, which implies that the probability of a baby being a girl is 1 - 0.526 = 0.474. Understanding how to calculate probabilities is essential for solving questions related to outcomes in a given scenario.
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Introduction to Probability

Independent Events

Independent events are those whose outcomes do not affect each other. In this case, the gender of each child is independent of the others, meaning the probability of each child being a girl remains constant regardless of the genders of the other children. This concept is crucial for calculating the overall probability of multiple events occurring together.
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Probability of Multiple Independent Events

Binomial Probability Formula

The binomial probability formula is used to determine the probability of a specific number of successes in a fixed number of independent trials, given a constant probability of success. For this question, we can use the formula to find the probability of having all four children as girls, which involves raising the probability of having a girl to the power of the number of children (0.474^4). This formula is fundamental in scenarios involving multiple trials with two possible outcomes.
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Related Practice
Textbook Question

In Exercises 21-28, find the probability and answer the questions.


Genetics: Eye Color Each of two parents has the genotype brown/blue, which consists of the pair of alleles that determine eye color, and each parent contributes one of those alleles to a child. Assume that if the child has at least one brown allele, that color will dominate and the eyes will be brown. (The actual determination of eye color is more complicated than that.)


b. What is the probability that a child of these parents will have the blue/blue genotype?

Textbook Question

Denomination Effect

In Exercises 13–16, use the data in the following table. In an experiment to study the effects of using four quarters versus a \$1 bill, some college students were given four quarters and others were given a \$1 bill, and they could either keep the money or spend it on gum. The results are summarized in the table (based on data from “The Denomination Effect,” by Priya Raghubir and Joydeep Srivastava, Journal of Consumer Research, Vol. 36).



Denomination Effect


b. Find the probability of randomly selecting a student who kept the money, given that the student was given four quarters.


Textbook Question

In Exercises 21-28, find the probability and answer the questions.


Guessing Birthdays On their first date, Kelly asks Mike to guess the date of her birth, not including the year.


b. Would it be unlikely for him to guess correctly on his first try?

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Textbook Question

Births in the United States In the United States, the true probability of a baby being a boy is 0.512 (based on the data available at this writing). For a family having three children, find the following.


b. The probability that all three children are boys.

Textbook Question

Corporate Officers and Committees The Self Driving Unicycle Company was recently successfully funded via Kickstarter and must now appoint a president, chief executive officer (CEO), chief operating officer (COO), and chief financial officer (CFO), and chief human resources officer (CHR). It must also appoint a strategic planning committee with five different members. There are 15 qualified candidates, and officers can also serve on the committee.


b. How many different ways can a committee of five be appointed?


Textbook Question

Dice and Coins


c. Find the probability that when a six-sided die is rolled, the outcome is 7.