/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 4 Common Names. The U.S. Census Bu... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Common Names. The U.S. Census Bureau says that the 10 most common names in the United States are (in order) Smith, Johnson, Williams, Brown, Jones, Miller, Davis, Garcia, Rodriguez, and Wilson. These names account for \(9.6 \%\) of all U.S. residents. Out of curiosity, you look at the authors of the textbooks for your current courses. There are 9 authors in all. Would you be surprised if none of the names of these authors were among the 10 most common? (Assume that authors' names are independent and follow the same probability distribution as the names of all residents.)

Short Answer

Expert verified
No, it would not be surprising, as there is a 55.1% chance none have common names.

Step by step solution

01

Determine the Probability of a Single Author's Name

The probability of a single author's name being one of the 10 most common names from the list is the probability we are given, which is 0.096 or 9.6%. This means there is a 9.6% chance that an author's name is among those 10 names.
02

Calculate the Probability of a Single Author Not Having a Common Name

To find the probability that a single author's name is not one of the 10 most common names, we subtract the probability of the name being common from 1: \[ P( ext{not common}) = 1 - 0.096 = 0.904. \] So, there is a 90.4% chance that an author's name is not among those 10 names.
03

Find the Probability that None of the Authors Have a Common Name

Since the authors' names are assumed to be independent, we can multiply the probabilities of each author's name not being common to find the probability that none of the 9 authors have a common name:\[ P( ext{none common}) = 0.904^9. \]Calculating gives us approximately 0.551.
04

Conclusion on Surprise

The probability calculated in Step 3 is approximately 0.551, or 55.1%. A probability higher than 50% suggests it's more likely than not that none of the authors have one of the 10 most common names. Therefore, it would not be surprising if none of the authors had one of those names.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Common Names
Everyone is curious to know if their name is popular or not. The U.S. Census Bureau provides a list of the 10 most common names in the United States, which includes Smith, Johnson, Williams, Brown, Jones, Miller, Davis, Garcia, Rodriguez, and Wilson. These names are shared by a significant portion of the population, about 9.6%. What this means is that approximately one out of every ten people have one of these last names. Understanding the distribution of common names can be an interesting way to relate with the demographic variety and cultural influences within a country.
When you look at situations such as a group of textbook authors and find none share one of these common names, it's a subtle way of exploring probabilities and are not really so unusual, as we'll delve into next.
Independence in Probability
In probability, independence refers to situations where the occurrence of one event does not affect the probability of another. When we assume that the names of textbook authors are independent, it means that the probability of one author's name being common doesn't impact the likelihood of another author's name also being common.
In our exercise, this principle of independence is crucial. We assume each author's name follows the same probability distribution as the general population. This allows us to use multiplication of probabilities to find the joint probability of all events.
  • The chance of one author's name not being common is calculated.
  • This probability is then used for each author independently.
  • We then compute the probability that none of the authors have a common name by multiplying these independent probabilities.
By understanding independence, we can make reliable predictions about probabilities in everyday contexts.
Probability Distribution
A probability distribution presents all possible outcomes of a random variable and their associated probabilities. In the context of common names, the probability distribution is quite straightforward. It tells us that there is a 9.6% chance any randomly chosen individual from the U.S. population has one of the 10 most common names.
Should we select a name randomly, understanding this distribution allows predictions about how likely that name matches one of the common ones. Here are some key highlights:
  • The probability of having a common name is denoted as 0.096.
  • The probability of a name not being common is simply 1 minus this value, which is 0.904.
  • By understanding these probabilities, we calculate the odds of outcomes involving more people, like all authors in our scenario.
This simple yet powerful way to categorize probabilities aids in making informed decisions in statistics.
Statistical Analysis
Statistical analysis involves interpreting data to make predictions and decisions. By calculating different probabilities, we apply statistical methods to understand real-world phenomena. In our exercise on common names, we explored the probability that none of a group of authors have one of the country's 10 most common names.
Here's the process broken down:
  • We first identified individual probabilities of names not being common.
  • Then, by using the concept of independent events, we multiplied these probabilities.
  • The result gave us a new statistical insight: it's over 50% likely that none of the authors have a common name.
Through statistical analysis, such as this, we can validate our expectations and understand tendencies in a logical, mathematical framework.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Here are the probabilities that a randomly selected high school student used these different tobacco products:- \(-\) $$ \begin{array}{lll} P(A)=0.08 & P(B)=0.21 & P(C)=0.19 \\ P(A \text { and } B)=0.06 & P(A \text { and } C)=0.03 & P(B \text { and } C)=0.06 \\ P(A \text { and } B \text { and } C)=0.02 & & \end{array} $$ Make a Venn diagram of the events A, B, and C. As in Eigure I3.4 (page 297), mark the probabilities of every intersection involving these events. Use this diagram for Excercises 13.4.5 through 13.4Z Do You Use Tobacco Products? What is the probability that a randomly selected high school st udent did not use any tobacco product?

Lost Internet References. Internet sites often vanish or move so that references to them can't be followed. In fact, \(47 \%\) of Internet sites referenced in major medical journals are lost. 5 If a paper contains seven Internet references, what is the probability that all seven are still good? What specific assumptions did you make to calculate this probability?

Of people who died in the United States in recent years, \(78 \%\) were non- Hispanic White, \(12 \%\) were non-Hispanic Black, \(7 \%\) were Hispanic, and \(3 \%\) were Asian. (This ignores a small number of deaths among other races.) Diabetes caused \(2.5 \%\) of deaths among non-Hispanic Whites, 4.4\% among non- Hispanic Blacks, 4.7\% among Hispanics, and 4.2\% among Asians. The probability that a randomly chosen death is a non-Hispanic White person and died of diabetes is about a. \(0.81 .\) b. \(0.025\). c. \(0.020\).

The Probability of a Flush. A poker player holds a flush when all five cards in the hand belong to the same suit (clubs, diamonds, hearts, or spades). We will find the probability of a flush when five cards are drawn in succession from the top of the deck. Remember that a deck contains 52 cards, 13 of each suit, and that when the deck is well shuffled, each card drawn is equally likely to be any of those that remain in the deck. a. Concentrate on spades. What is the probability that the first card drawn is a spade? What is the conditional probability that the second card drawn is a spade, given that the first is a spade? (Hint: How many cards remain? How many of these are spades?) b. Continue to count the remaining cards to find the conditional probabilities of a spade for the third, the fourth, and the fifth card drawn, given in each case that all previous cards are spades. c. The probability of drawing five spades in succession from the top of the deck is the product of the five probabilities you have found. Why? What is this probability? d. The probability of drawing five hearts or five diamonds or five clubs is the same as the probability of drawing five spades. What is the probability that the five cards drawn all belong to the same suit?

A Probability Teaser. Let's assume it is safe to say that people are either male or female at birth 18 and that each child born is equally likely to be a boy or a girl and that the sexes of successive children are independent. If we let BG mean that the older child is a boy and the younger child is a girl, then each of the combinations BB, BG, GB, and GG has probability \(0.25\). Ashley and Brianna each have two children. a. You know that at least one of Ashley's children is a boy. What is the conditional probability that she has two boys? b. You know that Brianna's older child is a boy. What is the conditional probability that she has two boys?

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.