| 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. 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 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. A sample of 9 production managers with over 15 years of experience has an average salary of $71,000 and a sample standard deviation of $18,000. Assuming that s = 18,000 is a reasonable estimate for what sample size would be needed to ensure that we could estimate the true mean salary of all production managers with more than 15 years experience within $4200 if we wish to be 95% confident? Place your answer, as a whole number, in the blank. Do not use a dollar sign, a comma, or any other stray mark. For examples, 34 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. A sample of 9 production managers with over 15 years of experience has an average salary of $71,000 and a sample standard deviation of $18,000. Assuming that the salaries of production managers with over 15 years experience are normally distributed, you can be 95% confident that the mean salary for all production managers with at least 15 years of experience is between what two numbers. Place your LOWER limit, rounded to a whole number, in the first blank. Do not use a dollar sign, a comma, or any other stray mark. For example, 54321 would be a legitimate entry. . Place your UPPER limit, rounded to a whole number, in the second blank. Do not use a dollar sign, a comma, or any other stray mark. For example, 65432 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. 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. 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 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. Assume 50 random samples of the same sample size are taken from a population, and a 90% confidence interval is constructed from each sample. How many of the intervals would you expect to contain the true population mean? Answer: Round your answer to a whole number value as necessary. For example, 37 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 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: Round your answer to 4 decimal places as necessary. For example, 0.1357 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. 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. 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. Part 2 of 3 -Question 8 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 < < 115.0 Reset SelectionQuestion 9 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.decrease C.increase D.increase or decrease, depending on the sample data Reset SelectionQuestion 10 of 201.0 PointsAt 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 C.0.0084 D.0.0054 Reset SelectionQuestion 11 of 201.0 PointsCompute where t20 has a t-distribution with 20 degrees of freedom. A.0.8233 B.0.1767 C.0.6466 D.0.5334 Reset SelectionQuestion 12 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.0.4684 B.0.5316 C.0.2658 D.0.7342 Reset SelectionQuestion 13 of 201.0 PointsA previous study of nickels showed that the standard deviation of the weight of nickels is 150 milligrams. How many nickels does a coin counter manufacturer need to weigh so that she can be 98% confident that her sample mean is within 25 milligrams of the true average weight of a nickel? A.36 B.196 C.239 D.139 Reset SelectionQuestion 14 of 201.0 PointsCompute where t15 has a t-distribution with 15 degrees of freedom. A.0.93606 B.0.7639 C.0.03197 D.0.96803 Reset SelectionQuestion 15 of 201.0 PointsWhich of the following will make a confidence interval narrower and more precise? A.Larger sample size and lower confidence level B.Larger sample size and higher confidence level C.Smaller sample size and lower confidence level D.Smaller sample size and higher confidence level Reset SelectionQuestion 16 of 201.0 PointsThe t- distribution for developing a confidence interval for a mean has _____ degrees of freedom. A.n - 1 B.n + 1 C.n - 2 D.n Reset SelectionQuestion 17 of 201.0 PointsConfidence intervals are a function of which of the following three things? A.The sample, the variable of interest, and the degrees of freedom B.The sampling distribution, the confidence level, and the degrees of freedom C.The data in the sample, the confidence level, and the sample size D.The population, the sample, and the standard deviation Reset SelectionQuestion 18 of 201.0 PointsIn constructing a confidence interval estimate for a population mean, when we replace with the sample standard deviation (s), we introduce a new source of variability and the sampling distribution we use is: A.chi-square distribution B.F- distribution C.t -distribution D.the normal distribution Reset SelectionPart 3 of 3 -Question 19 of 201.0 PointsIn general, increasing the confidence level will narrow the confidence interval, and decreasing the confidence level widens the interval. True FalseReset SelectionQuestion 20 of 201.0 PointsIn developing a confidence interval for the population standard deviation, , we make use of the fact that the sampling distribution of the sample standard deviation s is not the normal distribution or the t-distribution, but rather a right-skewed distribution called the chi-square distribution, which (for this procedure) has n – 1 degrees of freedom. True FalseReset Selection |
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