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Peck/Devore-Statistics: Exp & Analysis of Data 7/e (Homework)

James Finch

Statistics, section 2, Fall 2019

Instructor: Dr. Friendly

Current Score : 0 / 24

Due : Sunday, January 27, 2030 23:30 EST

Last Saved : n/a Saving...  ()

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  • Instructions

    Create your course assignments by selecting questions from our bank of end-of-section exercises.

    In this assignment we present several textbook question types found in Statistics: The Exploration and Analysis of Data 7/e by Roxy Peck and Jay L. Devore, published by Brooks/Cole. This demo assignment allows many submissions and allows you to try another version of the same question for practice wherever the problem has randomized values.

Assignment Submission

For this assignment, you submit answers by question parts. The number of submissions remaining for each question part only changes if you submit or change the answer.

Assignment Scoring

Your last submission is used for your score.

1. 0/2 points  |  Previous Answers PeckDevStat7 6.E.008. My Notes
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In a small city, approximately 20% of those eligible are called for jury duty in any one calendar year. People are selected for jury duty at random from those eligible, and the same individual cannot be called more than once in the same year.
(a) What is the probability that a particular eligible person in this city is selected two years in a row?
Incorrect: Your answer is incorrect.

(b) What is the probability that a particular eligible person in this city is selected three years in a row?
Incorrect: Your answer is incorrect.
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2. –/4 points PeckDevStat7 6.E.009. My Notes
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Jeanie is a bit forgetful, and if she doesn't make a "to do" list, the probability that she forgets something she is supposed to do is .7. Tomorrow she intends to run three errands, and she fails to write them on her list.
(a) What is the probability that Jeanie forgets all three errands?


What assumptions did you make to calculate this probability?
Events are .

(b) What is the probability that Jeanie remembers at least one of the three errands?


(c) What is the probability that Jeanie remembers the first errand but not the second or third?
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3. –/3 points PeckDevStat7 6.E.010. My Notes
Question Part
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1 2 3
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–/3
 
Approximately 20% of the calls to an airline reservation phone line result in a reservation being made.
(a) Suppose that an operator handles 10 calls. What is the probability that none of the 10 calls result in a reservation? (Give the answer to 3 decimals places.)


(b) What assumption did you make to calculate the probability in Part (a)?
    


(c) What is the probability that at least one call results in a reservation being made? (Give the answer to 3 decimals places.)
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4. –/9 points PeckDevStat7 6.E.013. My Notes
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–/9
 
Consider a system consisting of four components, as pictured in the diagram shown below. Components 1 and 2 form a series subsystem, as do Components 3 and 4. The two subsystems are connected in parallel. Suppose that P(1 works) = .5, P(2 works) = .5, P(3 works) = .5, and P(4 works) = .5 and that the four components work independently of one another.
(a) The 1-2 subsystem works only if both components work. What is the probability of this happening?


(b) What is the probability that the 1-2 subsystem doesn't work?


That the 3-4 subsystem doesn't work?


(c) The system won't work if the 1-2 subsystem doesn't work and if the 3-4 subsystem also doesn't work. What is the probability that the system won't work?


That it will work?


(d) How would the probability of the system working change if a 5-6 subsystem were added in parallel with the other two subsystems? (Give the answer to four decimal places.)


It .

(e) How would the probability that the system works change if there were three components in series in each of the two subsystems? (Give the answer to four decimal places.)


It .
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5. –/3 points PeckDevStat7 6.E.015. My Notes
Question Part
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1 2 3
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–/3
 
Is ultrasound a reliable method for determining the gender of an unborn baby? There is accompanying data on 1000 births in the table below.
Ultrasound
Predicted
Female		 Ultrasound
Predicted
Male
Actual Gender Is
Female		 425 49
Actual Gender Is
Male		 128 398
(a) Use the given information to estimate the probability that a newborn baby is female, given that the ultrasound predicted the baby would be female. (Give the answer to three decimal places.)


(b) Use the given information to estimate the probability that a newborn baby is male, given that the ultrasound predicted the baby would be male. (Give the answer to three decimal places.)


(c) Based on your answers to Parts (a) and (b), do you think ultrasound is equally reliable for predicting gender for boys and for girls?
    
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6. –/3 points PeckDevStat7 6.E.032. My Notes
Question Part
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–/3
 
A radio station that plays classical music has a "by request" program each Saturday evening. The percentages of requests for composers on a particular night are as follows.
Bach18%
Beethoven13%
Brahms4%
Dvorak7%
Mendelssohn7%
Mozart17%
Schubert8%
Schumann11%
Tchaikovsky12%
Wagner3%
Suppose that one of these requests is to be selected at random.
(a) What is the probability that the request is for one of the three B's?


(b) What is the probability that the request is not for one of the two S's?


(c) Neither Bach nor Wagner wrote any symphonies. What is the probability that the request is for a composer who wrote at least one symphony?
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