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##### apu math 302 quiz 3

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Question;Question 1 of 20;0.0/ 1.0 Points;Accepted 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 99% 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, 98.4 would be a legitimate entry. Correct175.5;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. Correct440.8;Answer Key;Question 2 of 20;0.0/ 1.0 Points;Accepted 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. Correct46.8;Place your UPPER limit, in hours, rounded to 1 decimal;place, in the second blank. For example, 12.3 would be a legitimate entry. Correct50.2;Answer Key;Question 3 of 20;0.0/ 1.0 Points;Accepted 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 25.9 mpg and a standard deviation of 9.5 mpg. If 30 such cars are;tested, what is the probability the average mpg achieved by these 30 cars will;be greater than 28?;Answer;Correct.1037 Round your answer to;4 decimal places as necessary. For;example, 0.1357 would be a legitimate entry.;Answer Key;Feedback: This is a sampling distribution problem with? =;25.9.? = 9.5, and sample size n = 30.;f[z=frac{28-25.9}{9.5/sqrt{30}} = 1.210755f];P(z > 1.210755) = 1 ? NORMSDIST(1.210755) = 0.1130;Or you can compute the probability without having to compute;z first;P(x-bar > 28) = 1 ? NORMDIST(28, 25.9, 9.5/SQRT(30);TRUE) = 0.1130;Question 4 of 20;1.0/ 1.0 Points;Accepted 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 Correct.322.;For example,.678 would be a legitimate entry. Place your UPPER limit, rounded to 3 decimal;places, in the second blank Correct.478. For example,.789 would be a legitimate entry.;Answer Key:.;Question 5 of 20;1.0/ 1.0 Points;Accepted 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 95% 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. Correct6.3;Place your UPPER limit, in hours, rounded to 1 decimal;place, in the second blank. For example, 12.3 would be a legitimate entry. Correct9.3;Answer Key;Question 6 of 20;1.0/ 1.0 Points;Accepted 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 marketing research consultant hired by Coca-Cola is;interested in determining the proportion of customers who favor Coke over other;soft drinks. A random sample of 400 consumers was selected from the market;under investigation and showed that 53% favored Coca-Cola over other brands.;Compute a 95% confidence interval for the true proportion of;people who favor Coke. Place your LOWER limit, rounded to 3 decimal places, in;the first blank Correct.481. For;example,.345 would be a legitimate entry. Place your UPPER limit in the second;blank Correct.579. For example,.456;would be a legitimate entry.;Answer Key;Question 7 of 20;0.0/ 1.0 Points;Accepted 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 90% 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. Correct231.5;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. Correct384.9;Answer Key;Part 2 of 3 - 10.0/;11.0 Points;Question 8 of 20;1.0/ 1.0 Points;In constructing a confidence interval estimate for a;population mean, when we replace f$sigma f$;with the sample standard deviation (s), we introduce a new source of;variability and the sampling distribution we use is;A.F- distribution;B.the normal distribution;C.chi-square;distribution;Correct D.t;-distribution;Answer Key;Question 9 of 20;1.0/ 1.0 Points;A food snack manufacturer samples 15 bags of pretzels off;the assembly line and weighed their contents. If the sample mean is 10.0 and;the sample standard deviation is 0.15, find the 95% confidence interval;estimate for the true mean.;A.(9.96, 10.04);B.(9.68, 10.32);C.(9.97, 10.80);Correct D.(9.92;10.08);Answer Key;Question 10 of 20;1.0/ 1.0 Points;In 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.50;B.39;C.166;Correct;Answer Key;Question 11 of 20;0.0/ 1.0 Points;If you increase the confidence level, the confidence;interval ____________.;A.stays the same;B.decreases;C.increases;Incorrect;D.may increase or decrease, depending on the sample data;Answer Key;Question 12 of 20;1.0/ 1.0 Points;The 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.;Correct A.0.15;B.0.85;C.0.70;D.0.30;Answer Key;Question 13 of 20;1.0/ 1.0 Points;At a large department store, the average number of years of;employment for a cashier is 5.7 with a standard deviation of 1.8 years. If the;number of years of employment at this department store is normally distributed;what is the probability that a cashier selected at random has worked at the;store for over 10 years?;A.0.4916;B.0.9916;Correct C.0.0084;D.0.0054;Answer Key;Question 14 of 20;1.0/ 1.0 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?;Correct A.1330;B.1400;C.1250;D.1100;Answer Key;Question 15 of 20;1.0/ 1.0 Points;From a sample of 500 items, 30 were found to be defective.;The point estimate of the population proportion defective will be;A.30;B.0.60;C.16.667;Correct D..06;Answer Key;Question 16 of 20;1.0/ 1.0 Points;The upper limit of the 90% confidence interval for the;population proportion p, given that n = 100, and f$hat{p}f$;= 0.20 is;A.0.4684;Correct B.0.2658;C.0.5316;D.0.7342;Answer Key;Question 17 of 20;1.0/ 1.0 Points;Which of the following will make a confidence interval;narrower and more precise?;A.Larger sample size;and higher confidence level;B.Smaller sample size;and lower confidence level;Correct C.Larger;sample size and lower confidence level;D.Smaller sample size;and higher confidence level;Answer Key;Question 18 of 20;1.0/ 1.0 Points;The t- distribution for developing a confidence interval for;a mean has _____ degrees of freedom.;A.n - 2;B.n + 1;Correct C.n - 1;D.n;Answer Key;Part 3 of 3 - 2.0/;2.0 Points;Question 19 of 20;1.0/ 1.0 Points;The lower limit of the 95% confidence interval for the;population proportion p, given that n = 300, and f$hat{p}f$;= 0.10 is 0.1339.;Correct;True;False;Answer Key;Question 20 of 20;1.0/ 1.0 Points;The upper limit of the 90% confidence interval for the;population proportion p, given that n = 100, and f$hat{p}f$ = 0.20 is 0.2341.;Correct;True;False;Answer Key

Paper#62415 | Written in 18-Jul-2015

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