Exam 3 Review Part II

Exam 3 Review Part - 3 The Hartnett Co states that their widgets last for a 10 years period 94 of the time a For samples of size 175 what are the

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1. A National Science Foundation poll found that out of 653 randomly chosen college students,123 indicated they plan on pursuing a career in a field associated with the natural sciences. a. Find a 92% % confidence interval for the proportion of all college students who plan on pursuing a career in a field associated with the natural sciences. b. Interpret the 92% confidence interval. c. Find a 97% confidence interval for the proportion of all college students who plan on pursuing a career in a field associated with the natural sciences. d. Interpret the 97% confidence interval. e. Is the confidence interval valid? Why or why not? (6 pts.) 2. Finding P-values a. Given H a : p ≠ p 0 , what is the P-value if the test statistic is determined to be z = -1.23? (3 pts.) b. Given H a : p > p 0 , what is the P-value if the test statistic is determined to be z = -2.15? (3 pts.) c. Given H a : p < p 0 , what is the P-value if the test statistic is determined to be z = -1.75? (3 pts.)
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Unformatted text preview: 3. The Hartnett Co. states that their widgets last for a 10 years period 94% of the time. a. For samples of size 175, what are the mean and standard deviation of the sampling distribution of sample proportion? (4 pts.) b. For a sample of size 175, what is the probability that the sample proportion of widgets lasting for a 10 year period is higher than 96%? c. For a sample of size 175, what is the probability that the sample proportion of widgets lasting for a 10 year period is higher than 85%?? (4 pts.) 4. The National Association of Realtors estimates that 23% of all homes purchased in 2004 were considered investment properties. If a sample of 800 homes sold in 2004 is obtained what is the probability that at least 175 homes are going to be used as investment property?. Test the claims using an α = 0.05 level of significance. (25 pts.) Assumptions Hypotheses Test Statistic P-value Conclusions...
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This note was uploaded on 06/16/2011 for the course STAT 201 taught by Professor Li during the Fall '07 term at South Carolina.

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Exam 3 Review Part - 3 The Hartnett Co states that their widgets last for a 10 years period 94 of the time a For samples of size 175 what are the

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