HomeWork_7

# HomeWork_7 - b Compute a 95 confidence interval for p 3 It...

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Home Work 7 1. In May, 2010 the National Department of Transportation reported the results of the survey. One focus of the survey was to determine the level of cell phone use by drivers while they are in the act of driving a motor passenger vehicle. Data collected by observers at randomly selected intersections across the country revealed that in a sample of 1,165 drivers, 35 were using their cell phone. a. Is the sample size large enough to construct a valid confidence interval for p , the true proportion of drivers who are using a sell phone while driving? b. Compute a 95% confidence interval for p . 2. In a study of homicide on the job, researchers of the Center of the National Development collected data on workplaces where an employee was murdered. In a sample of 105 cases, 65 of the homicides occurred during night hours (between 9 p.m. and 6 a.m.). a. Is the sample size large enough to construct a valid confidence interval for p , the true proportion of on-the-job homicide cases that occurred at night?
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Unformatted text preview: b. Compute a 95% confidence interval for p . 3. It costs you \$10 to draw a sample of size n = 1 and measure the attribute of interest. You have a budget of \$1,500. a. Do you have sufficient funds to estimate the population mean for the attribute of interest with a 95% confidence interval 5 units in width? Assume 14 = σ . b. If you used a 90% confidence level, would your answer to part a change? Explain. 4. A gigantic warehouse located in Tampa, Florida, stores approximately 60 million empty aluminum beer and soda cans. Recently, a fire occurred at the warehouse. The smoke from the fire contaminated many of the cans with blackspot, rendering them unusable. A University of South Florida statistician was hired by the insurance company to estimate p, the true proportion of cans in the warehouse that were contaminated by the fire. How many aluminum cans should be randomly sampled to estimate p to within 0.02 with 90% confidence?...
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## This note was uploaded on 02/06/2012 for the course ECON 103 taught by Professor Gispy during the Spring '11 term at Prairie State College .

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