2015 2- 2ª Ava Parcial - Questões Subj - Estatística II

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2015.02 – Estatística II – 2ª Avaliação Parcial – Prova Presencial – Questões Subjetivas 25 a 30.
Nome________________________________Matricula___________________Data_______________Hora______________
25. Uma empresa especializada na fabricação de paraquedas afirma que o índice de falhas de seu principal paraquedas não é mais do que 1%. Você realiza um teste de hipótese para determinar se a afirmação da empresa é falsa. Quando ocorrerá um erro tipo I ou tipo II? Qual é mais sério?
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26. Em um anúncio, uma pizzaria alega que o tempo de entrega é inferior a 30 minutos. Uma seleção aleatória de 19 tempos de entrega tem uma média de 28,5 minutos e um desvio-padrão amostral de 3,3 minutos. Teste a hipótese da pizzaria com um nível de significância de 5%.
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27. Considere os dados sobre uma pesquisa realizada com os orçamentos e os gastos brutos mundiais de 25 filmes mais caros da Century Fox apresentou um coeficiente de correlação como sendo r~0,83773. Teste a significância dessa correlação. Use .
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28. (CESPE/UnB- adaptada)
A tabela e as estatísticas mostradas acima correspondem ao estudo realizado por um engenheiro acerca da resistência Y (em kg) à tração de 6 fios de determinado material, considerando-se os respectivos diâmetros X (em 0,1 mm).
Mostre através de um diagrama de dispersão se os dados abaixo apresentam ou não uma correlação entre as variáveis, justificando sua resposta, apresentando os cálculos do coeficiente de correlação:
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15_______________________________________________________________________________________________________29. Um engenheiro de segurança registra a distância de frenagem de dois tipos de pneus. Cada amostra selecionada aleatoriamente tem 35 pneus. Os resultados dos testes são mostrados na figura. Em =0,10 , o engenheiro pode apoiar a afirmação de que a distância de frenagem média é diferente para os dois tipos de pneus? 
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30. A Zogby Internacional declara que 45% das pessoas nos Estados Unidos são a favor de tornar a venda de cigarro ilegal dentro dos próximos 10 anos. Você decide testar essa afirmação e entrevista uma amostra de 200 pessoas, dentre as quais, 49% são a favor da lei. Com , há evidência o bastante para apoiar a afirmação?
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QUESTÃO
	
C (certa)
	
D (meio certa)
	
E (errada)
	25
	
	
	
	26
	
	
	
	27
	
	
	
	28
	
	
	
	29
	
	
	
	30
	
	
	
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