Intro Stats
4th Edition
ISBN: 9780321826275
Author: Richard D. De Veaux
Publisher: PEARSON
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Chapter 10, Problem 21E
In Exercises 17 to 23, for the reports about statistical studies, identify the following items (if possible). If you can’t tell, then say so—this often happens when we read about a survey.
- a) The population
- b) The population parameter of interest
- c) The sampling frame
- d) The sample
- e) The sampling method, including whether or not randomization was employed
- f) Who (if anyone) was left out of the study
- g) Any potential sources of bias you can detect and any problems you see in generalizing to the population of interest
21. Roadblock State police set up a roadblock to estimate the percentage of cars with up-to-date registration, insurance, and safety inspection stickers. They usually find problems with about 10% of the cars they stop.
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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
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Months
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(x)
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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
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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 10 Solutions
Intro Stats
Ch. 10.2 - Various claims are often made for surveys. Why is...Ch. 10.4 - We need to survey a random sample of the 300...Ch. 10 - Texas AM Administrators at Texas AM University...Ch. 10 - Satisfied workers The managers of a large company...Ch. 10 - AM again The president of the university plans a...Ch. 10 - Satisfied respondents The companys annual report...Ch. 10 - Sampling students A professor teaching a large...Ch. 10 - Sampling satisfaction A company hoping to assess...Ch. 10 - Sampling AM students For each scenario, identify...Ch. 10 - Satisfactory satisfaction samples For each...
Ch. 10 - Survey students What problems do you see with...Ch. 10 - Happy employees The company plans to have the head...Ch. 10 - Student samples The university administration of...Ch. 10 - Surveying employees The company of Exercise 2 is...Ch. 10 - Roper Through their Roper Reports Worldwide, GfK...Ch. 10 - Student center survey For their class project, a...Ch. 10 - Drug tests Major League Baseball tests players to...Ch. 10 - Prob. 16ECh. 10 - In Exercises 17 to 23, for the reports about...Ch. 10 - Prob. 18ECh. 10 - Prob. 19ECh. 10 - Prob. 20ECh. 10 - In Exercises 17 to 23, for the reports about...Ch. 10 - In Exercises 17 to 23, for the reports about...Ch. 10 - In Exercises 17 to 23, for the reports about...Ch. 10 - Mistaken poll A local TV station conducted a...Ch. 10 - Another mistaken poll Prior to the mayoral...Ch. 10 - Parent opinion, part 1 In a large city school...Ch. 10 - Parent opinion, part 2 Lets revisit the school...Ch. 10 - Prob. 28ECh. 10 - Prob. 29ECh. 10 - Roller coasters An amusement park has opened a new...Ch. 10 - Playground, act two The survey described in...Ch. 10 - Wording the survey Two members of the PTA...Ch. 10 - Banning ephedra An online poll on a website asked:...Ch. 10 - Survey questions Examine each of the following...Ch. 10 - More survey questions Examine each of the...Ch. 10 - Phone surveys Any time we conduct a survey, we...Ch. 10 - Cell phone survey What about drawing a random...Ch. 10 - Fuel economy Occasionally, when I fill my car with...Ch. 10 - Prob. 40ECh. 10 - Prob. 41ECh. 10 - Quality control Sammys Salsa, a small local...Ch. 10 - A fish story Concerned about reports of discolored...Ch. 10 - Prob. 44ECh. 10 - More sampling methods Consider each of these...
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