Intro Stats
4th Edition
ISBN: 9780321826275
Author: Richard D. De Veaux
Publisher: PEARSON
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Chapter 7, Problem 36E
More misinterpretations A Sociology student investigated the association between a country’s Literacy Rate and Life Expectancy, and then drew the conclusions listed below. Explain why each statement is incorrect. (Assume that all the calculations were done properly.)
- a) The R2 of 64% means that the Literacy Rate determines 64% of the Life Expectancy for a country.
- b) The slope of the line shows that an increase of 5% in Literacy Rate will produce a 2-year improvement in Life Expectancy.
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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
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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 7 Solutions
Intro Stats
Ch. 7.4 - A scatterplot of house Price (in dollars) vs....Ch. 7.4 - A scatterplot of house Price (in dollars) vs....Ch. 7.4 - A scatterplot of house Price (in dollars) vs....Ch. 7.4 - A scatterplot of house Price (in dollars) vs....Ch. 7.4 - A scatterplot of house Price (in dollars) vs....Ch. 7.4 - Prob. 6JCCh. 7.6 - Prob. 7JCCh. 7.6 - Prob. 8JCCh. 7.6 - Prob. 9JCCh. 7 - True or false If false, explain briefly. a) We...
Ch. 7 - True or false II If false, explain briefly. a)...Ch. 7 - Prob. 3ECh. 7 - Prob. 4ECh. 7 - Bookstore sales revisited Recall the data we saw...Ch. 7 - Prob. 6ECh. 7 - Prob. 7ECh. 7 - Prob. 8ECh. 7 - Bookstore sales once more Here are the residuals...Ch. 7 - Prob. 10ECh. 7 - Prob. 11ECh. 7 - Prob. 12ECh. 7 - Prob. 13ECh. 7 - 14. Disk drives last time Here is a scatterplot of...Ch. 7 - Prob. 15ECh. 7 - Prob. 16ECh. 7 - More cereal Exercise 15 describes a regression...Ch. 7 - Prob. 18ECh. 7 - Another bowl In Exercise 15, the regression model...Ch. 7 - Prob. 20ECh. 7 - Cereal again The correlation between a cereals...Ch. 7 - Prob. 22ECh. 7 - Prob. 23ECh. 7 - Prob. 24ECh. 7 - Prob. 25ECh. 7 - Prob. 26ECh. 7 - Prob. 27ECh. 7 - Residuals Tell what each of the residual plots...Ch. 7 - Real estate A random sample of records of home...Ch. 7 - 30. Roller coaster The Mitch Hawker poll ranked...Ch. 7 - Prob. 31ECh. 7 - Prob. 32ECh. 7 - Real estate again The regression of Price on Size...Ch. 7 - Prob. 34ECh. 7 - Prob. 35ECh. 7 - More misinterpretations A Sociology student...Ch. 7 - Real estate redux The regression of Price on Size...Ch. 7 - 38. Another ride The regression of Duration of a...Ch. 7 - Prob. 39ECh. 7 - Prob. 40ECh. 7 - Prob. 41ECh. 7 - Prob. 42ECh. 7 - Prob. 43ECh. 7 - Prob. 44ECh. 7 - Prob. 45ECh. 7 - 46. Second inning 2010 Consider again the...Ch. 7 - Prob. 47ECh. 7 - Prob. 48ECh. 7 - Prob. 49ECh. 7 - Prob. 50ECh. 7 - Online clothes An online clothing retailer keeps...Ch. 7 - Online clothes II For the online clothing retailer...Ch. 7 - Prob. 53ECh. 7 - Success in college Colleges use SAT scores in the...Ch. 7 - SAT, take 2 Suppose we wanted to use SAT math...Ch. 7 - Prob. 56ECh. 7 - Prob. 57ECh. 7 - Prob. 58ECh. 7 - Prob. 59ECh. 7 - Drug abuse revisited Chapter 6, Exercise 42...Ch. 7 - Prob. 61ECh. 7 - Prob. 62ECh. 7 - Prob. 63ECh. 7 - 64. Chicken Chicken sandwiches are often...Ch. 7 - Prob. 65ECh. 7 - Prob. 66ECh. 7 - Prob. 67ECh. 7 - Prob. 68ECh. 7 - Prob. 69ECh. 7 - 70. Birthrates 2009 The table shows the number of...Ch. 7 - Prob. 71ECh. 7 - Prob. 72ECh. 7 - Prob. 73ECh. 7 - Prob. 74ECh. 7 - Hard water In an investigation of environmental...Ch. 7 - 76. Gators Wildlife researchers monitor many...Ch. 7 - Prob. 77ECh. 7 - Least squares Consider the four points (200,1950),...
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