Introductory Statistics
3rd Edition
ISBN: 9780135188927
Author: Gould, Robert, Ryan, Colleen N. (colleen Nooter)
Publisher: Pearson,
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Textbook Question
Chapter 3, Problem 27SE
Standard Deviation Is it possible for a standard deviation to be equal to zero? Explain.
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For unemployed persons in the United States, the average number of months of unemployment at the end of December 2009 was approximately seven months (Bureau of Labor Statistics, January 2010). Suppose the following data are for a particular region in upstate New York. The values in the first column show the number of
months unemployed and the values in the second column show the corresponding number of unemployed persons.
Months
Unemployed
Number
Unemployed
1
1029
2
1686
3
2269
4
2675
5
3487
6
4652
7
4145
8
3587
9
2325
10
1120
Let x be a random variable indicating the number of months a person is unemployed.
a. Use the data to develop an empirical discrete probability distribution for x (to 4 decimals).
(x)
f(x)
1
2
3
4
5
6
7
8
9
10
b. Show that your probability distribution satisfies the conditions for a valid discrete probability distribution.
The input in the box below will not be graded, but may be reviewed and considered by your instructor.
blank
c. What is the probability that a…
West Virginia has one of the highest divorce rates in the nation, with an annual rate of approximately 5 divorces per 1000 people (Centers for Disease Control and Prevention website, January 12, 2012). The Marital Counseling Center, Inc. (MCC) thinks that the high divorce rate in the state may require them to hire additional staff.
Working with a consultant, the management of MCC has developed the following probability distribution for x = the number of new clients for marriage counseling for the next year.
Excel File: data05-19.xls
x
10
f(x)
.05
20
30
.10
.10
40
.20
50
60
.35
.20
a. Is this probability distribution valid?
- Select your answer-
Explain.
f(x)
Σf(x)
Select your answer
Select your answer
b. What is the probability MCC will obtain more than 30 new clients (to 2 decimals)?
c. What is the probability MCC will obtain fewer than 20 new clients (to 2 decimals)?
d. Compute the expected value and variance of x.
Expected value
Variance
clients per year
squared clients per year
For unemployed persons in the United States, the average number of months of unemployment at the end of December 2009 was approximately seven months (Bureau of Labor Statistics, January 2010). Suppose the following data are for a particular region in upstate New York. The values in the first column show the number of
months unemployed and the values in the second column show the corresponding number of unemployed persons.
Months
Unemployed
Number
Unemployed
1
1029
2
1686
3
2269
4
2675
5
3487
6
4652
7
4145
8
3587
9
2325
10
1120
Let x be a random variable indicating the number of months a person is unemployed.
a. Use the data to develop an empirical discrete probability distribution for x (to 4 decimals).
(x)
f(x)
1
2
3
4
5
6
7
8
9
10
b. Show that your probability distribution satisfies the conditions for a valid discrete probability distribution.
The input in the box below will not be graded, but may be reviewed and considered by your instructor.
c. What is the probability that a person…
Chapter 3 Solutions
Introductory Statistics
Ch. 3 - Earnings A sociologist says, “Typically, men in...Ch. 3 - Houses A real estate agent claims that all things...Ch. 3 - Exercise Hours (Example 1) The histogram shows the...Ch. 3 - Sodium The following histogram shows the sodium...Ch. 3 - Tall Buildings The table shows the location and...Ch. 3 - Roller Coasters The table shows the names and...Ch. 3 - River Lengths (Example 2) The table shows the...Ch. 3 - Children of First Ladies This list represents the...Ch. 3 - 200-Meter Run The table show the gold medal...Ch. 3 - Olympic Swimming Times The table shows the...
Ch. 3 - Wedding Costs by Gender (Example 3) StatCrunch did...Ch. 3 - Wedding Costs by Experience StatCrunch did a...Ch. 3 - Surfing College students and surfers Rex Robinson...Ch. 3 - State College Tuition The tuition costs (in...Ch. 3 - Winter Temperatures San Jose and Denver (Example...Ch. 3 - Summer Temperatures L.A. and NYC The histograms...Ch. 3 - Weight Gain during Pregnancy (Example 5) The mean...Ch. 3 - Birth Length The mean birth length for U.S....Ch. 3 - Orange Juice Prices (Example 6) From Amazon.com,...Ch. 3 - Sibling Ages Four siblings are 2, 6, 9, and 10...Ch. 3 - Olympics In the most recent summer Olympics, do...Ch. 3 - Weights Suppose you have a data set with the...Ch. 3 - Home Prices (SC and TN) The prices (in $ thousand)...Ch. 3 - Home Prices (FL and GA) The prices (in $ thousand)...Ch. 3 - Drinkers The number of alcoholic drinks per week...Ch. 3 - Prob. 26SECh. 3 - Standard Deviation Is it possible for a standard...Ch. 3 - Standard Deviation Is it possible for a standard...Ch. 3 - Major League Baseball Runs (Example 7) The...Ch. 3 - Residential Energy Consumption (East) Data on...Ch. 3 - Pollution Index (Example 8) In 2017 a pollution...Ch. 3 - Pollution Index In 2017 a pollution index was...Ch. 3 - Heights and z-Scores The dotplot shows heights of...Ch. 3 - Heights Refer to the dotplot in the previous...Ch. 3 - Unusual IQs (Example 9) Wechsler IQ tests have a...Ch. 3 - Lengths of Pregnancy Distributions of gestation...Ch. 3 - Low-Birth-Weight Babies (Example 10) Babies born...Ch. 3 - Birth Lengths Babies born after 40 weeks gestation...Ch. 3 - Men’s Heights Assume that men’s heights have a...Ch. 3 - Women’s Heights Assume that women’s heights have a...Ch. 3 - Name two measures of the center of a distribution,...Ch. 3 - Name two measures of the variation of a...Ch. 3 - Marvel Movies (Example 11 and 13) The top ten...Ch. 3 - DC Movies The top seven movies based on DC comic...Ch. 3 - Top Seven Marvel Movies (Example 12) Use the data...Ch. 3 - Top Five DC Movies Use the data in Exercise 3.44,...Ch. 3 - Total Energy Consumption Data was collected on the...Ch. 3 - Industrial Energy Consumption Data was collected...Ch. 3 - Outliers a. In your own words, describe to someone...Ch. 3 - Center and Variation When you are comparing two...Ch. 3 - An Error A dieter recorded the number of calories...Ch. 3 - Baseball Strike In 1994, Major League Baseball...Ch. 3 - Home Prices Home prices in San Luis Obispo County...Ch. 3 - Youth Heights The National Longitudinal Survey...Ch. 3 - Senator Years in Office (Example 14) The following...Ch. 3 - MLB Player Ages The following histograms show the...Ch. 3 - Prob. 57SECh. 3 - Death Row: West The following table shows the...Ch. 3 - The Consumer Price Index (CPI) (Example 16)...Ch. 3 - Prob. 60SECh. 3 - Prob. 61SECh. 3 - Mean from a Histogram The histogram shows the...Ch. 3 - Poverty Rates The following boxplot shows the...Ch. 3 - Regional Population Density The figure shows the...Ch. 3 - Professional Sport Ticket Prices The following...Ch. 3 - BA Attainment The following boxplot shows the...Ch. 3 - Matching Boxplots and Histograms a. Report the...Ch. 3 - Matching Boxplots and Histograms Match each of the...Ch. 3 - Public Libraries Data at this text’s website show...Ch. 3 - Gas Taxes Data at this text’s website show the gas...Ch. 3 - Roller Coaster Heights (Example 17) The dotplot...Ch. 3 - Passing the Bar Exam The following dotplot shows...Ch. 3 - Exam Scores The five-number summary for a...Ch. 3 - Exam Scores The five-number summary for a...Ch. 3 - Prob. 75CRECh. 3 - Gas Taxes (West) The following table shows the gas...Ch. 3 - Final Exam Grades The data that follow are final...Ch. 3 - Speeding Tickets College students Diane Glover and...Ch. 3 - Heights The following graph shows the heights for...Ch. 3 - Marathon Times The following histogram of marathon...Ch. 3 - Prob. 81CRECh. 3 - Chain Restaurant Calories The New York Times...Ch. 3 - 12th-Grade Sleep The histogram shows hours of...Ch. 3 - For exercises 3.85 through 3.88, construct two...Ch. 3 - For exercises 3.85 through 3.88, construct two...Ch. 3 - For exercises 3.85 through 3.88, construct two...Ch. 3 - For exercises 3.85 through 3.88, construct two...Ch. 3 - Educational Attainment The tables below show the...Ch. 3 - Unemployment Rates The tables below show the 2015...Ch. 3 - Professional Sports Ticket Prices The following...Ch. 3 - Professional Sports Ticket Prices The following...Ch. 3 - Exam Scores An exam score has a mean of 80 and a...Ch. 3 - Boys’ Heights Three-year-old boys in the United...Ch. 3 - SAT and ACT Scores Quantitative SAT scores have a...Ch. 3 - Children’s Heights Mrs. Diaz has two children: a...Ch. 3 - Prob. 97CRECh. 3 - Students’ Ages Here are the ages of some students...Ch. 3 - Race Times The following graph shows the time it...Ch. 3 - Prob. 100CRECh. 3 - Prob. 101CRECh. 3 - Prob. 102CRE
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