Avaliação - Estatistica 3 - Tentaiva 3

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Revisar envio do teste: Atividade - Statistics 3
Estatística Avaliação e Certificado Acesse a atividade e o Certificado de Statistics 3
Revisar envio do teste: Atividade - Statistics 3 
Usuário GUILHERME LEDO FARIA BRANDAO
Curso Estatística
Teste Atividade - Statistics 3
Iniciado 22/11/19 23:31
Enviado 22/11/19 23:36
Status Completada
Resultado da tentativa 5 em 10 pontos 
Tempo decorrido 5 minutos
Resultados exibidos Respostas enviadas, Respostas corretas, Comentários
Pergunta 1
Resposta Selecionada: 
Resposta Correta: 
Feedback
da
resposta:
Skill: Determine the sampling distribution of the sample proportion and the sample
mean in a given situation and apply it to determine likelihoods. 
"multiple choice" question: select the correct answer.
There is 95% chance in a random sample of n=84 card users, the proportion of those
who pay their bills in full every month will be:
Between .20 and .40
Between .20 and .40
This is correct. When n=84, the mean and standard deviation of the
sampling distribution are: p = .30 and p(1−p)n−−−−−√=.3(1−.3)84−−−−−
−√=0.05, respectively.By the standard deviation rule, there is 95%
chance that the sample proportion will be within two standard deviations
of its mean. In other words, between .30 – 2(.05) = .20 and .30 + 2(.05) =
.40.
Pergunta 2
This is correct. This is the only incorrect statement. 
A 2015 CNN Money article provided the following information about the social class
distribution of U.S. adults.
 
Apply probability rules in order to find the likelihood of an event
"multiple choice" question: select the correct answer.
Two U.S. adults are chosen at random. What is the probability that
both adults belong to the same social class?
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Resposta Selecionada: 
Resposta Correta: 
Feedback
da
resposta:
 
.29 * .29 + .50 * .50 + .21 * .21
.29 * .29 + .50 * .50 + .21 * .21
This is correct. P(Both belong to the same social class) =
P(Both Lower class or Both Middle class or Both Upper
class) = [disjoint]P(Both Lower class) + P(Both Middle
class) + P(Both Upper class) = [independence].29 * .29 +
.50 * .50 + .21 * .21
Pergunta 3
Resposta Selecionada: 
Resposta Correta: 
A patient with a failing heart is waiting for a heart transplant. If a suitable transplant is
found, the patient’s chances of survival are much higher than the patient’s chances of
survival if a suitable transplant is not found. 
Let T be the event that a suitable Transplant is found. 
Let S be the event that the patient Survives 
The following probability tree summarizes the patient’s chances of finding a suitable
transplant and survival. 
Use the tree to answer the following questions:
Use Probability Trees as a tool to find probabilities
"multiple choice" question: select the correct answer.
Given that the patient survives, what is the probability that a suitable
transplant was found (what is P(T|S))? (Some answers were
rounded).
 
.225
.616
Pergunta 4
Resposta
Selecionada:
Resposta Correta:
Understand how probability quantifies uncertainty and relate the
probability of an event to the likelihood of the event occurring.
"multiple choice" question: select the correct answer.
Let A be the event that a document will reach its destination on time
using a certain service. If P(A)=.98
this means that:
 
The document will almost always reach its
destination on time
The document will almost always reach its
destination on time
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Feedback da resposta: This is correct.
Pergunta 5
Resposta Selecionada: 
Resposta Correta: 
Skill: Determine the sampling distribution of the sample proportion and the sample
mean in a given situation and apply it to determine likelihoods. 
"multiple choice" question: select the correct answer. 
Is it safe to assume that the sampling distribution of pˆ is approximately normal for
random samples of size n=21?
Yes, since n*(1-p) is greater than 10. 
No, since n*p is not greater than 10.
Pergunta 6
Resposta
Selecionada:
Resposta Correta:
Feedback da resposta:
The probability table below summarizes the information that a large cable company
provides about its customers:
 
 
Where: 
T is the event that a randomly chosen customer subscribes to TV service 
I is the event that a randomly chosen customer subscribes to Internet service
 
Create a probability table to organize and summarize information and
use it to find probabilities
"multiple choice" question: select the correct answer.
In context, the fact that P(Not T and Not I) = 0 means that:
 
All the customers subscribe to at least one of the
two services.
All the customers subscribe to at least one of the
two services.
This is correct.
Pergunta 7
Fit the binomial model when appropriate, and use it to perform
probability calculations.
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Resposta
Selecionada:
 
Resposta Correta:
"multiple choice" question: select the correct answer.
What are the mean and standard deviation of X, the number of
females out of the 10 chosen who are binge drinkers?
 
μx=10(0.15) −−−−−−−−√ , σx=10(0.15)(0.85)
μx=10(0.15) , σx=10(0.15)(0.85)−−−−−−−−−−−−√
Pergunta 8
Resposta
Selecionada:
Resposta
Correta:
Skill: Determine the sampling distribution of the sample proportion and the sample
mean in a given situation and apply it to determine likelihoods. 
"multiple choice" question: select the correct answer. 
Scores of the Math portion of the SAT (SAT-M) are known to have a national mean
μ=500and standard deviation σ=100. 
A random sample of n=400 high-school seniors was chosen and their average SAT-M
score was found to be x̅=522. 
Would this finding surprise you? 
Yes, since an average of 522 is larger than 500 and the sample
size (n=400) is large enough.
Yes, since an average of 522 is more than 4 standard deviations
above 500.
Pergunta 9
Resposta Selecionada: [Sem Resposta]
A large cable company provides the following information regarding
its customers:
· 50% of all customers subscribe to internet service.
· If a customer is an internet subscriber, there is 64% chance that
he/she is also a phone subscriber.
· If a customer is a phone subscriber, there is 80% chance that he/she
is also an internet subscriber.
Let A be the event that a customer subscribes to internet service
Let B be the event that a customer subscribes to phone service
Use the general multiplication rule to find P(A and B)
"multiple choice" question: select the correct answer.
What is the probability that a customer subscribes to both internet and
phone service?
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Sexta-feira, 22 de Novembro de 2019 23h36min45s BRT
Resposta Correta: P(A) * P(B|A) = .50 * .64 = .32
Pergunta 10
Resposta Selecionada: 
Resposta Correta: 
Feedback
da
resposta:
A family eats out twice a month – once during the first week of the monthand once
during the third week of the month, in one of the three local restaurants: R1, R2, or
R3. Thus the outcome (R3, R2) denotes that on a given month the family eats in R3
during the first week of the month and in R2 during the third week of the month. It is
possible for the family to eat at the same restaurant both on the first week and on the
third week of the month.
 
Apply probability rules in order to find the likelihood of an event
Find the probability of events in the case when all outcomes are
equally likely.
Determine the sample space of a random experiment and identify
which outcomes are included in a particular event
"multiple choice" question: select the correct answer.
A fair four sided die with the numbers 1,2,3, and 4 is rolled twice.
Thus, for example, the outcome (4, 1) denotes that the die landed on
a 4 on the first roll and on 1 on the second. What is the probability that
the sum of the numbers showing in the two rolls is 3?
 
1/8
1/8
This is correct. This experiment has 16 possible outcomes:
(1,1) (1,2) (1,3) (1,4)(2,1) (2,2) (2,4) (2,4)(3,1) (3,2) (3,3)
(3,4)(4,1) (4,2) (4,3) (4,4)and since the die is fair, all 16
outcomes are equally likely. In two of the 16 possible
outcomes the sum of the numbers is 3 [(1,2) and (2,1)] and
therefore the probability is 2/16=1/8.
← OK
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