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APUS MATH STATISTICS 302 QUIZ 3

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Question;Part 1 of 3 -Question 1 of 201.0 PointsAccepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. Senior management of a consulting services firm is concerned about a growing decline in the firm?s weekly number of billable hours. The firm expects each professional employee to spend at least 40 hours per week on work. In an effort to understand this problem better, management would like to estimate the standard deviation of the number of hours their employees spend on work-related activities in a typical week. Rather than reviewing the records of all the firm?s full-time employees, the management randomly selected a sample of size 51 from the available frame. The sample mean and sample standard deviations were 48.5 and 7.5 hours, respectively. Construct a 90% confidence interval for the standard deviation of the number of hours this firm?s employees spend on work-related activities in a typical week. Place your LOWER limit, in hours, rounded to 1 decimal place, in the first blank. For example, 6.7 would be a legitimate entry. Place your UPPER limit, in hours, rounded to 1 decimal place, in the second blank. For example, 12.3 would be a legitimate entry. Question 2 of 201.0 PointsAccepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. If a sample has 20 observations and a 95% confidence estimate for is needed, the appropriate value of the t-multiple required is. Place your answer, rounded to 3 decimal places, in the blank. For example, 4.567 would be a legitimate entry. Question 3 of 201.0 PointsAccepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. You are told that a random sample of 150 people from Iowa has been given cholesterol tests, and 60 of these people had levels over the ?safe? count of 200. Construct a 95% confidence interval for the population proportion of people in Iowa with cholesterol levels over 200. Place your LOWER limit, rounded to 3 decimal places, in the first blank. For example,.678 would be a legitimate entry. Place your UPPER limit, rounded to 3 decimal places, in the second blank. For example,.789 would be a legitimate entry.Question 4 of 201.0 PointsAccepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. If a sample has 25 observations and a 99% confidence estimate for is needed, the appropriate value of the t-multiple required is. Place your answer, rounded to 3 decimal places, in the blank. For example, 3.456 would be an appropriate entry. Question 5 of 201.0 PointsAccepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. The manufacturer of a new compact car claims the miles per gallon (mpg) for the gasoline consumption is mound-shaped and symmetric with a mean of 24.6 mpg and a standard deviation of 11.2 mpg. If 30 such cars are tested, what is the probability the average mpg achieved by these 30 cars will be greater than 27? Answer: Round your answer to 4 decimal places as necessary. For example, 0.1357 would be a legitimate entry. Question 6 of 201.0 PointsAccepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. The personnel department of a large corporation wants to estimate the family dental expenses of its employees to determine the feasibility of providing a dental insurance plan. A random sample of 12 employees reveals the following family dental expenses (in dollars): 115, 370, 250, 593, 540, 225, 177, 425, 318, 182, 275, and 228. Construct a 95% confidence interval estimate for the standard deviation of family dental expenses for all employees of this corporation. Place your LOWER limit, in dollars rounded to 1 decimal place, in the first blank. Do not use a dollar sign, a comma, or any other stray mark. For example, 123.4 would be a legitimate entry. Place your UPPER limit, in dollars rounded to 1 decimal place, in the second blank. Do not use a dollar sign, a comma, or any other stray mark. For example, 567.8 would be a legitimate entry. Question 7 of 201.0 PointsAccepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. A survey of 85 families showed that 36 owned at least one DVD player. Find the 99% confidence interval estimate of the true proportion of families who own at least one DVD player. Place your limits, rounded to 3 decimal places, in the blanks. Place the lower limit in the first blank and the upper limit in the second blank When entering your answer do not use any labels or symbols other than the decimal point. Simply provide the numerical values. For example, 0.123 would be a legitimate entry.Part 2 of 3 -Question 8 of 201.0 PointsFind the 95% confidence interval for the standard deviation of the lengths of pipes if a sample of 26 pipes has a standard deviation of 10 inches. A.14.0 < < 16.0 B.7.8 < < 13.8 C.74.0 < < 126.0 D.60.8 < < 190.5Reset SelectionQuestion 9 of 201.0 PointsThe average gas mileage of a certain model car is 26 miles per gallon. If the gas mileages are normally distributed with a standard deviation of 1.3, find the probability that a randomly selected car of this model has a gas mileage between 25.8 and 26.3 miles per gallon. A.0.15 B.0.85 C.0.70 D.0.30Reset SelectionQuestion 10 of 201.0 PointsCompute where t20 has a t-distribution with 20 degrees of freedom. A.0.5334 B.0.8233 C.0.1767 D.0.6466Reset SelectionQuestion 11 of 201.0 PointsA sample of 23 European countries found that the variance of life expectancy was 7.3 years. What is the 95% confidence interval estimate for the variance of life expectancy in Europe? A.27.2 < < 118.3 B.5.6 < < 10.3 C.4.4 < < 14.6 D.28.9 < < 115.0Reset SelectionQuestion 12 of 201.0 PointsThe t- distribution for developing a confidence interval for a mean has _____ degrees of freedom. A.n - 1 B.n C.n + 1 D.n - 2Reset SelectionQuestion 13 of 201.0 Points In order to be accepted into a top university, applicants must score within the top 5% on the SAT exam. Given that SAT test scores are normally distributed with a mean of 1000 and a standard deviation of 200, what is the lowest possible score a student needs to qualify for acceptance into the university? A.1330 B.1400 C.1250 D.1100Reset SelectionQuestion 14 of 201.0 PointsCompute where t15 has a t-distribution with 15 degrees of freedom. A.0.03197 B.0.96803 C.0.7639 D.0.93606Reset SelectionQuestion 15 of 201.0 PointsThe upper limit of the 90% confidence interval for the population proportion p, given that n = 100, and = 0.20 is A.0.5316 B.0.4684 C.0.2658 D.0.7342Reset SelectionQuestion 16 of 201.0 PointsIf you are constructing a confidence interval for a single mean, the confidence interval will___________ with an increase in the sample size. A.stay the same B.increase C.decrease D.increase or decrease, depending on the sample dataReset SelectionQuestion 17 of 201.0 PointsIn a study of elephants a researcher wishes to determine the average weight of a certain subspecies of elephants. From previous studies, the standard deviation of the weights of elephants in this subspecies is known to be 1500 pounds. How many elephants does the researcher need to weigh so that he can be 80% confident that the average weight of elephants in his sample is within 350 pounds of the true average weight for this subspecies? A.166 B.31 C.39 D.50Reset SelectionQuestion 18 of 201.0 PointsA researcher wishes to know, with 98% confidence, the percentage of women who wear shoes that are too small for their feet. A previous study conducted by the Academy of Orthopedic Surgeons found that 80% of women wear shoes that are too small for their feet. If the researcher wants her estimate to be within 3% of the true proportion, how large a sample is necessary? A.966 B.683 C.183 D.484Reset SelectionPart 3 of 3 -Question 19 of 201.0 PointsThe 95% confidence interval for the population mean, given that the sample size n = 49 and the population standard deviation = 7, is. True FalseReset SelectionQuestion 20 of 201.0 PointsA 90% confidence interval estimate for a population mean is determined to be 72.8 to 79.6. If the confidence level is reduced to 80%, the confidence interval becomes narrower. True FalseReset Selection

 

Paper#61871 | Written in 18-Jul-2015

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