Introduction to Statistics and Data Analysis
5th Edition
ISBN: 9781305115347
Author: Roxy Peck; Chris Olsen; Jay L. Devore
Publisher: Brooks Cole
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Chapter 11.1, Problem 1E
Consider two populations for which μ1 = 30, σ1 = 2, μ2 = 25, and σ2 = 3. Suppose that two independent random
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Calculate the mean for Study Hours and Test Scores.
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Calculate the standard deviation for Study Hours (X) and Test Scores (Y).
Determine the correlation coefficient
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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.
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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
Chapter 11 Solutions
Introduction to Statistics and Data Analysis
Ch. 11.1 - Consider two populations for which 1 = 30, 1 = 2,...Ch. 11.1 - An individual can take either a scenic route to...Ch. 11.1 - Prob. 3ECh. 11.1 - Prob. 4ECh. 11.1 - The article Plugged In, but Tuned Out (USA TODAY,...Ch. 11.1 - Prob. 6ECh. 11.1 - Prob. 7ECh. 11.1 - The paper If Its Hard to Read, Its Hard to Do...Ch. 11.1 - Is injecting medical cement effective in reducing...Ch. 11.1 - Prob. 10E
Ch. 11.1 - Prob. 11ECh. 11.1 - The paper Mood Food: Chocolate and Depressive...Ch. 11.1 - Prob. 13ECh. 11.1 - Example 11.1 looked at a study comparing students...Ch. 11.1 - Prob. 15ECh. 11.1 - Prob. 16ECh. 11.1 - A newspaper story headline reads Gender Plays Part...Ch. 11.1 - Prob. 18ECh. 11.1 - Fumonisins are environmental toxins produced by a...Ch. 11.1 - A researcher at the Medical College of Virginia...Ch. 11.1 - Do certain behaviors result in a severe drain on...Ch. 11.2 - Suppose that you were interested in investigating...Ch. 11.2 - Head movement evaluations are important because...Ch. 11.2 - To determine if chocolate milk was as effective as...Ch. 11.2 - The humorous paper Will Humans Swim Faster or...Ch. 11.2 - The study described in the paper Marketing Actions...Ch. 11.2 - Prob. 27ECh. 11.2 - The paper Less Air Pollution Leads to Rapid...Ch. 11.2 - The paper The Truth About Lying in Online Dating...Ch. 11.2 - Prob. 30ECh. 11.2 - Prob. 31ECh. 11.2 - The paper Quantitative Assessment of Glenohumeral...Ch. 11.2 - Two proposed computer mouse designs were compared...Ch. 11.2 - Prob. 34ECh. 11.2 - Prob. 35ECh. 11.2 - The authors of the paper Ultrasound Techniques...Ch. 11.3 - Some people seem to believe that you can fix...Ch. 11.3 - Prob. 38ECh. 11.3 - After the 2010 earthquake in Haiti, many...Ch. 11.3 - Prob. 40ECh. 11.3 - The report Audience Insights: Communicating to...Ch. 11.3 - Prob. 42ECh. 11.3 - Prob. 43ECh. 11.3 - Prob. 44ECh. 11.3 - The article Fish Oil Staves Off Schizophrenia (USA...Ch. 11.3 - The report Young People Living on the Edge...Ch. 11.3 - Prob. 47ECh. 11.3 - Prob. 48ECh. 11.3 - Prob. 49ECh. 11.3 - Prob. 50ECh. 11.3 - Prob. 51ECh. 11.3 - The article Spray Flu Vaccine May Work Better Than...Ch. 11.3 - Prob. 53ECh. 11.3 - The following quote is from the article Canadians...Ch. 11.3 - Prob. 55ECh. 11.3 - Women diagnosed with breast cancer whose tumors...Ch. 11.3 - Prob. 57ECh. 11.4 - The paper The Psychological Consequences of Money...Ch. 11.4 - An experiment to determine if an online...Ch. 11.4 - The paper Ready or Not? Criteria for Marriage...Ch. 11 - Prob. 61CRCh. 11 - Prob. 62CRCh. 11 - A deficiency of the trace element selenium in the...Ch. 11 - Prob. 64CRCh. 11 - Prob. 65CRCh. 11 - In a study of a proposed treatment for diabetes...Ch. 11 - When a surgeon repairs injuries, sutures (stitched...Ch. 11 - Prob. 68CRCh. 11 - In a study of memory recall, eight students from a...Ch. 11 - As part of a study to determine the effects of...Ch. 11 - Prob. 71CRCh. 11 - Prob. 72CRCh. 11 - The article Truth and DARE: Tracking Drug...Ch. 11 - The article Softball Sliding Injuries (American...Ch. 11 - Prob. 75CRCh. 11 - Wayne Gretzky was one of ice hockeys most prolific...Ch. 11 - Heres one to sink your teeth into: The authors of...Ch. 11 - Prob. 78CRCh. 11 - Dentists make many people nervous. To see whether...Ch. 11 - Prob. 80CRCh. 11 - Prob. 81CRCh. 11 - Both surface soil and subsoil specimens were taken...
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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. c. What is the probability that a person…arrow_forwardIn Gallup's Annual Consumption Habits Poll, telephone interviews were conducted for a random sample of 1014 adults aged 18 and over. One of the questions was "How many cups of coffee, if any, do you drink on an average day?" The following table shows the results obtained (Gallup website, August 6, 2012). Excel File: data05-23.xls Number of Cups per Day Number of Responses 0 365 264 193 3 4 or more 91 101 Define a random variable x = number of cups of coffee consumed on an average day. Let x = 4 represent four or more cups. Round your answers to four decimal places. a. Develop a probability distribution for x. x 0 1 2 3 4 f(x) b. Compute the expected value of x. cups of coffee c. Compute the variance of x. cups of coffee squared d. Suppose we are only interested in adults that drink at least one cup of coffee on an average day. For this group, let y = the number of cups of coffee consumed on an average day. Compute the expected value of y. Compare it to the expected value of x. The…arrow_forwardIn Gallup's Annual Consumption Habits Poll, telephone interviews were conducted for a random sample of 1014 adults aged 18 and over. One of the questions was "How many cups of coffee, if any, do you drink on an average day?" The following table shows the results obtained (Gallup website, August 6, 2012). Excel File: data05-23.xls Number of Cups per Day Number of Responses 0 365 264 193 2 3 4 or more 91 101 Define a random variable x = number of cups of coffee consumed on an average day. Let x = 4 represent four or more cups. Round your answers to four decimal places. a. Develop a probability distribution for x. x 0 1 2 3 f(x) b. Compute the expected value of x. cups of coffee c. Compute the variance of x. cups of coffee squared d. Suppose we are only interested in adults that drink at least one cup of coffee on an average day. For this group, let y = the number of cups of coffee consumed on an average day. Compute the expected value of y. Compare it to the expected value of x. The…arrow_forward
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