WEBASSIGN ACCESS FOR PROBABILITY & STATS
9th Edition
ISBN: 9780357893111
Author: DEVORE
Publisher: CENGAGE L
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Chapter 14.3, Problem 31E
A random sample of smokers was obtained, and each individual was classified both with respect to gender and with respect to the age at which he/she first started smoking. The data in the accompanying table is consistent with summary results reported in the article “Cigarette Tar Yields in Relation to Mortality in the Cancer Prevention Study II Prospective Cohort” (British Med. J., 2004: 72–79).
| Gender | |||
| Male | Female | ||
| Age | <16 | 25 | 10 |
| 16-17 | 24 | 32 | |
| 18-20 | 28 | 17 | |
| >20 | 19 | 34 | |
a. Calculate the proportion of males in each age category, and then do the same for females. Based on these proportions, does it appear that there might be an association between gender and the age at which an individual first smokes?
b. Carry out a test of hypotheses to decide whether there is an association between the two factors.
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In 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
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0
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x
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2
3
f(x)
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Develop a probability distribution for the duration of a service call.
Duration of Call
x
f(x)
1
2
3
4
Which of the following probability distribution graphs accurately represents the data set?
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What is the probability a service call will take three hours?
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A psychologist determined that the number of sessions required to obtain the trust of a new patient is either 1, 2, or 3. Let x be a random variable indicating the number of sessions required to gain the patient's trust. The following probability function has been proposed.
x
f(x)
for x = 1, 2, or 3
a. Consider the required conditions for a discrete probability function, shown below.
f(x) ≥0
Σf(x) = 1
(5.1)
(5.2)
Does this probability distribution satisfy equation (5.1)?
Select
Does this probability distribution satisfy equation (5.2)?
Select
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c. What is the probability that it takes at least 2 sessions to gain the patient's trust (to 3 decimals)?
Chapter 14 Solutions
WEBASSIGN ACCESS FOR PROBABILITY & STATS
Ch. 14.1 - What conclusion would be appropriate for an...Ch. 14.1 - The article Racial Stereotypes in Childrens...Ch. 14.1 - It is hypothesized that when homing pigeons are...Ch. 14.1 - The article Application of Methods for Central...Ch. 14.1 - An information-retrieval system has ten storage...Ch. 14.1 - The article The Gap Between Wine Expert Ratings...Ch. 14.1 - Criminologists have long debated whether there is...Ch. 14.1 - The article Psychiatric and Alcoholic Admissions...Ch. 14.1 - Prob. 9ECh. 14.1 - Prob. 10E
Ch. 14.1 - Prob. 11ECh. 14.2 - Consider a large population of families in which...Ch. 14.2 - A study of sterility in the fruit fly (Hybrid...Ch. 14.2 - Prob. 14ECh. 14.2 - A certain type of flashlight is sold with the four...Ch. 14.2 - Let X = the number of adult police contacts for a...Ch. 14.2 - In a genetics experiment, investigators looked at...Ch. 14.2 - The article A Probabilistic Analysis of Dissolved...Ch. 14.2 - Each headlight on an automobile undergoing an...Ch. 14.2 - Prob. 20ECh. 14.2 - Prob. 21ECh. 14.2 - The article A Method for the Estimation of Alcohol...Ch. 14.2 - The article Nonbloated Burned Clay Aggregate...Ch. 14.3 - The accompanying two-way table was constructed...Ch. 14.3 - In an investigation of alcohol use among college...Ch. 14.3 - Contamination of various food products is an...Ch. 14.3 - The article Human Lateralization from Head to...Ch. 14.3 - Prob. 28ECh. 14.3 - The accompanying data on degree of spirituality...Ch. 14.3 - Three different design configurations are being...Ch. 14.3 - A random sample of smokers was obtained, and each...Ch. 14.3 - Eclosion refers to the emergence of an adult...Ch. 14.3 - Prob. 33ECh. 14.3 - Prob. 34ECh. 14.3 - Prob. 35ECh. 14.3 - Consider the accompanying 2 3 table displaying...Ch. 14 - The article Birth Order and Political Success...Ch. 14 - Does the phase of the moon have any bearing on...Ch. 14 - Prob. 39SECh. 14 - The authors of the article Predicting Professional...Ch. 14 - The accompanying two-way frequency table appears...Ch. 14 - Prob. 42SECh. 14 - Prob. 43SECh. 14 - Prob. 44SECh. 14 - Prob. 45SECh. 14 - The NCAA basketball tournament begins with 64...Ch. 14 - Have you ever wondered whether soccer players...Ch. 14 - Do the successive digits in the decimal expansion...Ch. 14 - Prob. 49SE
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- A technician services mailing machines at companies in the Phoenix area. Depending on the type of malfunction, the service call can take 1, 2, 3, or 4 hours. The different types of malfunctions occur at about the same frequency. Develop a probability distribution for the duration of a service call. Which of the following probability distribution graphs accurately represents the data set? Consider the required conditions for a discrete probability function, shown below.Does this probability distribution satisfy equation (5.1)?Does this probability distribution satisfy equation (5.2)? What is the probability a service call will take three hours? A service call has just come in, but the type of malfunction is unknown. It is 3:00 P.M. and service technicians usually get off at 5:00 P.M. What is the probability the service technician will have to work overtime to fix the machine today?arrow_forwardWest 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 10 20 f(x) .05 .10 11 30 40 50 60 .10 .20 .35 .20 a. Is this probability distribution valid? Yes Explain. greater than or equal to 0 f(x) Σf(x) equal to 1 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 yeararrow_forwardReconsider the patient satisfaction data in Table 1. Fit a multiple regression model using both patient age and severity as the regressors. (a) Test for significance of regression. (b) Test for the individual contribution of the two regressors. Are both regressor variables needed in the model? (c) Has adding severity to the model improved the quality of the model fit? Explain your answer.arrow_forward
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