Introductory Statistics (2nd Edition)
2nd Edition
ISBN: 9780321978271
Author: Robert Gould, Colleen N. Ryan
Publisher: PEARSON
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Chapter 2, Problem 39SE
U.S. Distribution of wealth (Example 8) Michael Norton (of Harvard) and Dan Ariely (of Duke) did a survey reported in Harvard Magazine (Nov-Dec 2011). They asked respondents to estimate how much of the wealth is held by each quintile (fifth) of the people in the United States. The top quintile is wealthiest
a. In truth, the top fifth (in terms of wealth) actually held about what percentage of the wealth?
b. Which figures (Ideal, Estimate, or Truth) show the least variation?
c. Which figures (Ideal, Estimate, or Truth) show the most variation?
d. Do people making estimates tend to underestimate or to overestimate the proportion of wealth held by top
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3. Bayesian Inference – Updating Beliefs
A medical test for a rare disease has the following characteristics:
Sensitivity (true positive rate): 99%
Specificity (true negative rate): 98%
The disease occurs in 0.5% of the population.
A patient receives a positive test result.
Questions:
a) Define the relevant events and use Bayes’ Theorem to compute the probability that the patient actually has the disease.b) Explain why the result might seem counterintuitive, despite the high sensitivity and specificity.c) Discuss how prior probabilities influence posterior beliefs in Bayesian inference.d) Suppose a second, independent test with the same accuracy is conducted and is also positive. Update the probability that the patient has the disease.
Chapter 2 Solutions
Introductory Statistics (2nd Edition)
Ch. 2 - Body Mass Index The Dotplot shows body mass index...Ch. 2 - Cholesterol Levels The dotplot shows the...Ch. 2 - Ages of CEOs The histogram shows frequencies for...Ch. 2 - Sleep Hours The relative frequency histogram shows...Ch. 2 - Televisions (Example 1) The histogram shows the...Ch. 2 - Exercise Hours The histogram shows the...Ch. 2 - Shoes The graph is a dotplot of the number of...Ch. 2 - Condo Rental The dotplot shows rental prices per...Ch. 2 - Speeding Tickets (Example 2) A teacher asks 90...Ch. 2 - Breakfast Predict the shape of the distribution of...
Ch. 2 - Arm spans (Example 3) According to the ancient...Ch. 2 - Tuition The distribution of in-state annual...Ch. 2 - Ages of CEOs (Example 4) From the histogram in...Ch. 2 - Sleep Hours From the histogram shown in Exercise...Ch. 2 - Commute Times (Example 5) Use the histograms to...Ch. 2 - Spending on Clothes The histograms show the...Ch. 2 - Education (Example 6) In 2012, the General Social...Ch. 2 - Siblings The histogram shows the distribution of...Ch. 2 - Years of Education The GSS asked people how many...Ch. 2 - Hours Worked In the 2012 General Social Survey,...Ch. 2 - Matching Histograms match each of the following...Ch. 2 - Matching Histograms Match each of the following...Ch. 2 - Matching Match each description with the correct...Ch. 2 - Matching Match each description with the correct...Ch. 2 - Eating Out and jobs College students Jacqueline...Ch. 2 - Comparing Weights of Baseball and Soccer Players...Ch. 2 - Textbook Prices The table shows prices of 50...Ch. 2 - SAT scores The following table shows a random...Ch. 2 - Animal Longevity The following table in Exercise...Ch. 2 - Animal Gestation Periods The accompanying table...Ch. 2 - Tax Rate A StatCrunch survey asked people what...Ch. 2 - Pets A StatCrunch survey asked people whether they...Ch. 2 - Law School Tuition Data are shown for the cost of...Ch. 2 - Text Messages Recently, 115 users of StatCrunch...Ch. 2 - Beer, Calories Data are available on the number of...Ch. 2 - Beer, Alcohol Data are available on the percent...Ch. 2 - Changing Multiple-Choice Answers When Told Not to...Ch. 2 - Preventable Deaths According to the World Health...Ch. 2 - U.S. Distribution of wealth (Example 8) Michael...Ch. 2 - Education The graph shows the education of...Ch. 2 - Political Party Affiliation: Men The 2012 General...Ch. 2 - Political Party Affiliation Women The 2012 General...Ch. 2 - Prob. 43SECh. 2 - Retail Car Sales With gas prices rising, as they...Ch. 2 - Majors The table gives information on college...Ch. 2 - Adoptions The table gives information on the top...Ch. 2 - Garage The accompanying graph shows the...Ch. 2 - Body Image A student has gathered data on...Ch. 2 - Pie Chart of Sleep Hours The pie chart reports the...Ch. 2 - Age and Gender The following graph shows the ages...Ch. 2 - Musicians Survey: StatCrunch Graph The...Ch. 2 - Cell Phone Use Refer to the accompanying bar...Ch. 2 - Television The table shows the first few entries...Ch. 2 - Job The table shows the job categories for some...Ch. 2 - Hormone Replacement Therapy The use of the drug...Ch. 2 - E-Music The bar graph shows information reported...Ch. 2 - Hormone Replacement Therapy Again The following...Ch. 2 - Holding Your Breath A group of students held their...Ch. 2 - Global Temperatures The histograms show the...Ch. 2 - Employment after Law School Accredited law schools...Ch. 2 - Position for Breathing The graph shows the results...Ch. 2 - Opinions on Global Warming People were asked...Ch. 2 - Create a dotplot that has at least 10 observations...Ch. 2 - Create a dotplot that has at least 10 observations...Ch. 2 - Traffic Cameras College students Jeannette Mujica,...Ch. 2 - Ideal Weight Thirty-nine students (26 women and 13...Ch. 2 - MPH The graphs show the distribution of...Ch. 2 - Shoe Sizes The graph shows shoe sizes for men and...Ch. 2 - CEO Salaries Predict the shape of the distribution...Ch. 2 - Cigarettes A physician asks all of his patients to...Ch. 2 - Changing Multiple-Choice Answers When Told to Do...Ch. 2 - ER Visits for Injuries The graph shows the rates...
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