Concept explainers
Wilcoxon Signed-Rank Test for n > 30 When you are performing a Wilcoxon signed-rank test and the
In Exercises 9 and 10, perform the Wilcoxon signed-rank test using the test statistic for n > 30.
9. Fuel Additive A petroleum engineer wants to know whether a certain fuel additive improves a car’s gas mileage. To decide, the engineer records the gas mileages (in miles per gallon) of 33 randomly selected cars with and without the fuel additive. The table shows the results. At a = 0.10, can the engineer conclude that the gas mileage is improved?
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Chapter 11 Solutions
MYLAB STATISTICS: ELEMENTARY STATISTICS
- uppose automobile insurance companies gave annual premiums for top-rated companies in several states. The figure below shows box plots for the annual premium for urban customers in three states. Which state offers the lowest premium? Which state offers the highest premium?arrow_forwardWing Foot is a shoe franchise commonly found in shopping centers across the United States. Wing Foot knows that its stores will not show a profit unless they gross over $940,000 per year. Let A be the event that a new Wing Foot store grosses over $940,000 its first year. Let B be the event that a store grosses over $940,000 its second year. Wing Foot has an administrative policy of closing a new store if it does not show a profit in either of the first two years. Assume that the accounting office at Wing Foot provided the following information: 58% of all Wing Foot stores show a profit the first year; 72% of all Wing Foot store show a profit the second year (this includes stores that did not show a profit the first year); however, 86% of Wing Foot stores that showed a profit the first year also showed a profit the second year. Compute P(B|Ac). Round your answer to the nearest hundredth.arrow_forwardYou draw two cards from a standard deck of 52 cards, but before you draw the second card, you put the first one back and reshuffle the deck. If you get a3on the first card, find the probability of drawing a 3 for the second card.arrow_forward
- Do bonds reduce the overall risk of an investment portfolio? Let x be a random variable representing annual percent return for the Vanguard Total Stock Index (all Stocks). Let y be a random variable representing annual return for the Vanguard Balanced Index (60% stock and 40% bond). For the past several years, assume the following data. Compute the coefficient of variation for each fund. Round your answers to the nearest tenth. x: 14 0 37 21 35 23 24 -14 -14 -17 y: 8 -2 29 17 22 17 17 -2 -3 -8arrow_forwardWhat percentage of the general U.S. population have bachelor's degrees? Suppose that the Statistical Abstract of the United States, 120th Edition, gives the following percentage of bachelor’s degrees by state. For convenience, the data are sorted in increasing order. 17 18 18 18 19 20 20 20 21 21 21 21 21 22 22 22 22 22 23 23 24 24 24 24 24 25 25 25 25 26 26 26 26 26 26 27 27 27 28 28 28 29 29 31 31 32 32 34 35 38 Illinois has a bachelor's degree percentage rate of about 18%. Into what quartile does this rate fall?arrow_forwardWhat percentage of the general U.S. population have bachelor's degrees? Suppose that the Statistical Abstract of the United States, 120th Edition, gives the following percentage of bachelor’s degrees by state. For convenience, the data are sorted in increasing order. 17 18 18 18 19 20 20 20 21 21 21 21 21 22 22 22 22 22 23 23 24 24 24 24 24 25 25 25 25 26 26 26 26 26 26 27 27 27 28 28 28 29 29 31 31 32 32 34 35 38 Illinois has a bachelor's degree percentage rate of about 18%. Into what quartile does this rate fall?arrow_forward
- Find the range for the following sample data. x 23 17 11 30 27arrow_forwardDo bonds reduce the overall risk of an investment portfolio? Let x be a random variable representing annual percent return for the Vanguard Total Stock Index (all Stocks). Let y be a random variable representing annual return for the Vanguard Balanced Index (60% stock and 40% bond). For the past several years, assume the following data. Compute the sample mean for x and for y. Round your answer to the nearest tenth. x: 11 0 36 22 34 24 25 -11 -11 -22 y: 9 -3 28 14 23 16 14 -3 -4 -9arrow_forwardDo bonds reduce the overall risk of an investment portfolio? Let x be a random variable representing annual percent return for the Vanguard Total Stock Index (all Stocks). Let y be a random variable representing annual return for the Vanguard Balanced Index (60% stock and 40% bond). For the past several years, assume the following data. Compute the range for variable y. X 12 0 36 21 35 23 24 -12 -12 -21 Y 10 -2 26 15 22 18 15 -2 -3 -10arrow_forward
- Do bonds reduce the overall risk of an investment portfolio? Let x be a random variable representing annual percent return for the Vanguard Total Stock Index (all Stocks). Let y be a random variable representing annual return for the Vanguard Balanced Index (60% stock and 40% bond). For the past several years, assume the following data. Compute the range for variable y. X 12 0 36 21 35 23 24 -12 -12 -21 Y 10 -2 26 15 22 18 15 -2 -3 -10arrow_forwardDo bonds reduce the overall risk of an investment portfolio? Let x be a random variable representing annual percent return for the Vanguard Total Stock Index (all Stocks). Let y be a random variable representing annual return for the Vanguard Balanced Index (60% stock and 40% bond). For the past several years, assume the following data. Compute the range for variable x. X 15 0 37 23 33 25 26 -15 -15 -23 Y 6 -1 28 18 24 17 18 -1 -2 -6arrow_forward7.16. If the probability density of X is given by g kx³ for x>0 f(x) = (1+2x)6 0 10-01, elsewhere trolls inf ( 2X density of the random variable Y = where k is an appropriate constant, find the probability 1+2X distribution of Y, and thus determine the value of k. 7 Identify thearrow_forward
- Holt Mcdougal Larson Pre-algebra: Student Edition...AlgebraISBN:9780547587776Author:HOLT MCDOUGALPublisher:HOLT MCDOUGALFunctions and Change: A Modeling Approach to Coll...AlgebraISBN:9781337111348Author:Bruce Crauder, Benny Evans, Alan NoellPublisher:Cengage Learning