New Semester
Started
Get
50% OFF
Study Help!
--h --m --s
Claim Now
Question Answers
Textbooks
Find textbooks, questions and answers
Oops, something went wrong!
Change your search query and then try again
S
Books
FREE
Study Help
Expert Questions
Accounting
General Management
Mathematics
Finance
Organizational Behaviour
Law
Physics
Operating System
Management Leadership
Sociology
Programming
Marketing
Database
Computer Network
Economics
Textbooks Solutions
Accounting
Managerial Accounting
Management Leadership
Cost Accounting
Statistics
Business Law
Corporate Finance
Finance
Economics
Auditing
Tutors
Online Tutors
Find a Tutor
Hire a Tutor
Become a Tutor
AI Tutor
AI Study Planner
NEW
Sell Books
Search
Search
Sign In
Register
study help
business
statistics informed decisions using data
Understanding Basic Statistics 7th Edition Charles Henry Brase, Corrinne Pellillo Brase - Solutions
Archaeology: Cultural Affi liation “Unknown cultural affi liations and loss of identity at high elevations.” These are words used to propose the hypothesis that archaeological sites tend to lose their identity as altitude extremes are reached. This idea is based on the notion that prehistoric
Critical Thinking: Different Confi dence Levels(a) Suppose that a 95% confi dence interval for a difference of proportions contains both positive and negative numbers. Will a 99% confi dence interval based on the same data necessarily contain both positive and negative numbers? Explain. What about
Focus Problem: Wood-Duck Nests In the Focus Problem at the beginning of this chapter, a study was described comparing the hatch ratios of wood-duck nesting boxes. Group I nesting boxes were well separated from each other and well hidden by available brush. There were a total of 474 eggs in group I
Statistical Literacy When are two random samples independent?
Statistical Literacy When are two random samples dependent?For each hypothesis test in Problems 3–10, please provide the following information:(i) What is the level of signifi cance? State the null and alternate hypotheses.(ii) Check Requirements What sampling distribution will you use? What
Agriculture: Bell Peppers The following data represent soil water content(percentage of water by volume) for independent random samples of soil taken from two experimental fi elds growing bell peppers (Reference: Journal of Agricultural, Biological, and Environmental Statistics). Note: These data
Stocks: Retail and Utility How profi table are different sectors of the stock market? One way to answer such a question is to examine profi t as a percentage of stockholder equity. A random sample of 32 retail stocks such as Toys “ R” Us, Best Buy, and Gap was studied for x1, profi t as a
Wildlife: Wolves A random sample of 18 adult male wolves from the Canadian Northwest Territories gave an average weight x1 5 98 lb with estimated sample standard deviation s1 5 6.5 lb. Another sample of 24 adult male wolves from Alaska gave an average weight x2 5 90 lb with estimated sample
Wildlife: Wolves A random sample of 17 wolf litters in Ontario, Canada, gave an average of x1 5 4.9 wolf pups per litter with estimated sample standard deviation s1 5 1.0. Another random sample of 6 wolf litters in Finland gave an average of x2 5 2.8 wolf pups per litter with sample standard
Survey Response: Validity The book Survey Responses: An Evaluation of Their Validity, by E. J. Wentland and K. Smith (Academic Press), includes studies reporting the accuracy of answers to questions from surveys. A study by Locander and others considered the question “Are you a registered
Survey Response: Validity Locander and others (see reference in Problem 7)also studied the accuracy of responses on questions involving more sensitive material than voter registration. From public records, individuals were identifi ed as having been charged with drunken driving not less than 6
Statistical Literacy In general, are chi-square distributions symmetrical or skewed? If skewed, are they skewed right or left?
Statistical Literacy For chi-square distributions, as the number of degrees of freedom increases, does any skewness increase or decrease? Do chi-square distributions become more symmetrical (and normal) as the number of degrees of freedom becomes larger and larger?
Statistical Literacy For chi-square tests of independence and of homogeneity, do we use a right-tailed, left-tailed, or two-tailed test?
Critical Thinking In general, how do the hypotheses for chi-square tests of independence differ from those for chi-square tests of homogeneity? Explain.
Critical Thinking Zane is interested in the proportion of people who recycle each of three distinct products: paper, plastic, and electronics. He wants to test the hypothesis that the proportion of people recycling each type of product differs by age group: 12–18 years old, 19–30 years old,
Critical Thinking Charlotte is doing a study on fraud and identity theft based both on source (checks, credit cards, debit cards, online banking/fi nance sites, other) and on gender of the victim. Describe the sampling method appropriate for a test of independence regarding source of fraud and
Interpretation: Test of Homogeneity Consider Zane’s study regarding products recycled and age group (see Problem 5). Suppose he found a sample x2 5 16.83.(a) How many degrees of freedom are used? Recall that there were 4 age groups and 3 products specifi ed. Approximate the P-value and conclude
Interpretation: Test of Independence Consider Charlotte’s study of source of fraud/identity theft and gender (see Problem 6). She computed sample x2 5 10.2.(a) How many degrees of freedom are used? Recall that there were 5 sources of fraud/identity theft and, of course, 2 genders. Approximate the
Psychology: Myers-Briggs The following table shows the Myers-Briggs personality preferences for a random sample of 406 people in the listed professions (Myers-Briggs Type Indicator Atlas of Type Tables, by Macdaid, McCaulley, and Kainz). E refers to extroverted and I refers to
Psychology: Myers-Briggs The following table shows the Myers-Briggs personality preferences for a random sample of 519 people in the listed professions (Myers-Briggs Type Indicator Atlas of Type Tables, by Macdaid, McCaulley, and Kainz). T refers to thinking and F refers to feeling.Personality
Archaeology: Pottery The following table shows site type and type of pottery for a random sample of 628 sherds at a location in Sand Canyon Archaeological Project, Colorado (The Sand Canyon Archaeological Project, edited by Lipe):Pottery Type Site Type Mesa Verde Black-on-White McElmo
Archaeology: Pottery The following table shows ceremonial ranking and type of pottery sherd for a random sample of 434 sherds at a location in the Sand Canyon Archaeological Project, Colorado (The Architecture of Social Integration in Prehistoric Pueblos, edited by Lipe and Hegmon):Ceremonial
Ecology: Buffalo The following table shows age distribution and location of a random sample of 166 buffalo in Yellowstone National Park (based on information from The Bison of Yellowstone National Park, National Park Service Scientifi c Monograph Series):Age Lamar District Nez Perce District
Psychology: Myers-Briggs The following table shows the Myers-Briggs personality preference and area of study for a random sample of 519 college students(Applications of the Myers-Briggs Type Indicator in Higher Education, edited by Provost and Anchors). In the table, IN refers to introvert,
Sociology: Movie Preference Mr. Acosta, a sociologist, is doing a study to see if there is a relationship between the age of a young adult (18 to 35 years old) and the type of movie preferred. A random sample of 93 adults revealed the following data.Test whether age and type of movie preferred are
Sociology: Ethnic Groups After a large fund drive to help the Boston City Library, the following information was obtained from a random sample of contributors to the library fund. Using a 1% level of signifi cance, test the claim that the amount contributed to the library fund is independent of
Focus Problem: Archaeology The Focus Problem at the beginning of the chapter refers to excavations at Burnt Mesa Pueblo in Bandelier National Monument. One question the archaeologists asked was: Is the raw material used by prehistoric Indians for stone tool manufacture independent of the
Statistical Literacy When drawing a scatter diagram, along which axis is the explanatory variable placed? Along which axis is the response variable placed?
Statistical Literacy Suppose two variables are positively correlated. Does the response variable increase or decrease as the explanatory variable increases?
Statistical Literacy Suppose two variables are negatively correlated. Does the response variable increase or decrease as the explanatory variable increases?
Statistical Literacy Describe the relationship between two variables when the correlation coeffi cient r is(a) near 1.(b) near 0.(c) near 1.
Critical Thinking: Linear Correlation Look at the following diagrams. Does each diagram show high linear correlation, moderate or low linear correlation, or no linear correlation? (a) Cengage Learning (b) Cengage Learning"
Critical Thinking: Linear Correlation Look at the following diagrams. Does each diagram show high linear correlation, moderate or low linear correlation, or no linear correlation? (a) Cengage Learning (b) Cengage Learning
Critical Thinking: Lurking Variables Over the past few years, there has been a strong positive correlation between the annual consumption of diet soda drinks and the number of traffi c accidents.(a) Do you think increasing consumption of diet soda drinks causes traffi c accidents? Explain.(b) What
Critical Thinking: Lurking Variables Over the past decade, there has been a strong positive correlation between teacher salaries and prescription drug costs.(a) Do you think paying teachers more causes prescription drugs to cost more? Explain.(b) What lurking variables might be causing the increase
Critical Thinking: Lurking Variables Over the past 50 years, there has been a strong negative correlation between average annual income and the record time to run 1 mile. In other words, average annual incomes have been rising while the record time to run 1 mile has been decreasing.(a) Do you think
Critical Thinking: Lurking Variables Over the past 30 years in the United States, there has been a strong negative correlation between the number of infant deaths at birth and the number of people over age 65.(a) Is the fact that people are living longer causing a decrease in infant mortalities at
Interpretation Trevor conducted a study and found that the correlation between the price of a gallon of gasoline and gasoline consumption has a linear correlation coeffi cient of 0.7. What does this result say about the relationship between price of gasoline and consumption? The study included
Interpretation Do people who spend more time on social networking sites spend more time using Twitter? Megan conducted a study and found that the correlation between the times spent on the two activities was 0.8. What does this result say about the relationship between times spent on the two
Veterinary Science: Shetland Ponies How much should a healthy Shetland pony weigh? Let x be the age of the pony (in months), and let y be the average weight of the pony (in kilograms). The following information is based on data taken from The Merck Veterinary Manual (a reference used in most
Health Insurance: Administrative Cost The following data are based on information from Domestic Affairs. Let x be the average number of employees in a group health insurance plan, and let y be the average administrative cost as a percentage of claims.(a) Make a scatter diagram and draw the line you
Meteorology: Cyclones Can a low barometer reading be used to predict maximum wind speed of an approaching tropical cyclone? Data for this problem are based on information taken from Weatherwise (Vol. 46, No. 1), a publication of the American Meteorological Society. For a random sample of tropical
Geology: Earthquakes Is the magnitude of an earthquake related to the depth below the surface at which the quake occurs? Let x be the magnitude of an earthquake(on the Richter scale), and let y be the depth (in kilometers) of the quake below the surface at the epicenter. The following is based on
Baseball: Batting Averages and Home Runs In baseball, is there a linear correlation between batting average and home run percentage? Let x represent the batting average of a professional baseball player, and let y represent the player’s home run percentage (number of home runs per 100 times at
University Crime: FBI Report Do larger universities tend to have more property crime? University crime statistics are affected by a variety of factors.The surrounding community, accessibility given to outside visitors, and many other factors infl uence crime rates. Let x be a variable that
Expand Your Knowledge: Effect of Scale on Scatter Diagram The initial visual impact of a scatter diagram depends on the scales used on the x and y axes. Consider the following data:x 1 2 3 4 5 6 y 1 4 6 3 6 7(a) Make a scatter diagram using the same scale on both the x and y axes(i.e., make sure
Expand Your Knowledge: Effect on r of Exchanging x and y Values Examine the computation formula for r, the sample correlation coeffi cient [formulas(1) and (2) of this section].(a) In the formula for r, if we exchange the symbols x and y, do we get a different result or do we get the same
Expand Your Knowledge: Using a Table to Test r The correlation coeffi cient r is a sample statistic. What does it tell us about the value of the population correlation coeffi cient r (Greek letter rho)? We will build the formal structure of hypothesis tests of r in Section 11.4. However, there is a
We do this by comparing the value r to an entry in Table 4-6. The value of a in the table gives us the probability of concluding that r ? 0 when, in fact, r 5 0 and there is no population correlation.We have two choices for a: a 5 0.05 or a 5 0.01.(a) Look at Problem 13 regarding the variables x 5
Expand Your Knowledge: Sample Size and Signifi cance of Correlation In this problem, we use Table 4-6 to explore the signifi cance of r based on different sample sizes. See Problem 21.(a) Is a sample correlation coeffi cient r 5 0.820 signifi cant at the a 5 0.01 level based on a sample size of n 5
Expand Your Knowledge: Correlation of Averages Fuming because you are stuck in traffi c? Roadway congestion is a costly item, in both time wasted and fuel wasted. Let x represent the average annual hours per person spent in traffi c delays and let y represent the average annual gallons of fuel
Why do smaller standard deviations sx and sy tend to increase the value of r?(c) Make a scatter diagram for the second set of data pairs. Verify that x 5 161, x2 5 4583, y 5 255, y2 5 12,565, and xy 5 7071.Compute r.(d) Compare r from part (a) with r from part (c). Do the data for averages have a
Statistical Literacy In the least-squares line yˆ 5 5 2x, what is the value of the slope? When x changes by 1 unit, by how much does yˆ change?
Statistical Literacy In the least squares line yˆ 5 5 1 3x, what is the marginal change in yˆ for each unit change in x?
Critical Thinking When we use a least-squares line to predict y values for x values beyond the range of x values found in the data, are we extrapolating or interpolating? Are there any concerns about such predictions?
Critical Thinking If two variables have a negative linear correlation, is the slope of the least-squares line positive or negative?
Critical Thinking: Interpreting Computer Printouts We use the form yˆ 5 a 1 bx for the least-squares line. In some computer printouts, the least-squares equation is not given directly. Instead, the value of the constant a is given, and the coeffi cient b of the explanatory or predictor variable is
Critical Thinking: Interpreting Computer Printouts Refer to the description of a computer display for regression described in Problem
The following Minitab display gives information regarding the relationship between the body weight of a child (in kilograms) and the metabolic rate of the child (in 100 kcal/24 hr). The data is based on information from The Merck Manual (a commonly used reference in medical schools and nursing
Economics: Entry-Level Jobs An economist is studying the job market in Denver-area neighborhoods. Let x represent the total number of jobs in a given neighborhood, and let y represent the number of entry-level jobs in the same neighborhood. A sample of six Denver neighborhoods gave the following
Ranching: Cattle You are the foreman of the Bar-S cattle ranch in Colorado.A neighboring ranch has calves for sale, and you are going to buy some to add to the Bar-S herd. How much should a healthy calf weigh? Let x be the age of the calf (in weeks), and let y be the weight of the calf (in
Weight of Car: Miles per Gallon Do heavier cars really use more gasoline?Suppose a car is chosen at random. Let x be the weight of the car (in hundreds of pounds), and let y be the miles per gallon (mpg). The following information is based on data taken from Consumer Reports (Vol. 62, No. 4).x 27
Basketball: Fouls Data for this problem are based on information from STATS Basketball Scoreboard. It is thought that basketball teams that make too many fouls in a game tend to lose the game even if they otherwise play well. Let x be the number of fouls that were more than (i.e., over and
Auto Accidents: Age Data for this problem are based on information taken from The Wall Street Journal. Let x be the age in years of a licensed automobile driver. Let y be the percentage of all fatal accidents (for a given age) due to speeding. For example, the fi rst data pair indicates that 36% of
Auto Accidents: Age Let x be the age of a licensed driver in years. Let y be the percentage of all fatal accidents (for a given age) due to failure to yield the right-of-way. For example, the fi rst data pair states that 5% of all fatal accidents of 37-year-olds are due to failure to yield the
Income: Medical Care Let x be per capita income in thousands of dollars. Let y be the number of medical doctors per 10,000 residents. Six small cities in Oregon gave the following information about x and y (based on information from Life in America’s Small Cities by G. S. Thomas, Prometheus
Violent Crimes: Prisons Does prison really deter violent crime? Let x represent percent change in the rate of violent crime and y represent percent change in the rate of imprisonment in the general U.S. population. For 7 recent years, the following data have been obtained (Source: The Crime Drop in
Education: Violent Crime The following data are based on information from the book Life in America’s Small Cities (by G. S. Thomas, Prometheus Books).Let x be the percentage of 16- to 19-year-olds not in school and not high school graduates. Let y be the reported violent crimes per 1000
Research: Patents The following data are based on information from the Harvard Business Review (Vol. 72, No. 1). Let x be the number of different research programs, and let y be the mean number of patents per program. As in any business, a company can spread itself too thin. For example, too many
Archaeology: Artifacts Data for this problem are based on information taken from Prehistoric New Mexico: Background for Survey (by D. E. Stuart and R. P. Gauthier, University of New Mexico Press). It is thought that prehistoric Indians did not take their best tools, pottery, and household items
Cricket Chirps: Temperature Anyone who has been outdoors on a summer evening has probably heard crickets. Did you know that it is possible to use the cricket as a thermometer? Crickets tend to chirp more frequently as temperatures increase. This phenomenon was studied in detail by George W. Pierce,
Expand Your Knowledge: Residual Plot The least-squares line usually does not go through all the sample data points x, y . In fact, for a specifi ed x value from a data pair (x, y), there is usually a difference between the predicted value and the y value paired with x. This difference is called the
Residual Plot: Miles per Gallon Consider the data of Problem 9.(a) Make a residual plot for the least-squares model.(b) Use the residual plot to comment about the appropriateness of the leastsquares model for these data. See Problem 19.
Critical Thinking: Exchange x and y in Least-Squares Equation(a) Suppose you are given the following (x, y) data pairs:x 1 3 4 y 2 1 6 Show that the least-squares equation for these data is y 5 0.066 1 1.393x(rounded to three digits after the decimal)(b) Now suppose you are given these (x, y) data
Expand Your Knowledge: Logarithmic Transformations, Exponential Growth Model There are several extensions of linear regression that apply to exponential growth and power law models. Problems 22–25 will outline some of these extensions. First of all, recall that a variable grows linearly over time
Expand Your Knowledge: Logarithmic Transformations, Exponential Growth Model Let x 5 day of observation and y 5 number of locusts per square meter during a locust infestation in a region of North Africa.x 2 3 5 8 10 y 2 3 12 125 630(a) Draw a scatter diagram of the (x, y) data pairs. Do you think a
Draw a scatter diagram of the x, y data pairs and compare this diagram with the diagram of part (a). Which graph appears to better fi t a straight line?(c) Use a calculator with regression keys to fi nd the linear regression equation for the data pairs x, y . What is the correlation coeffi
Expand Your Knowledge: Logarithmic Transformations, Power Law Model When we take measurements of the same general type, a power law of the form y 5 axb often gives an excellent fi t to the data. A lot of research has been conducted as to why power laws work so well in business, economics, biology,
Expand Your Knowledge: Logarithmic Transformations, Power Law Model Let x 5 boiler steam pressure in 100 lb/in.2 and let y 5 critical sheer strength of boiler plate steel joints in tons/in.2. We have the following data for a series of factory boilers.x 4 5 6 8 10 y 3.4 4.2 6.3 10.9 13.3(a) Make the
Critical Thinking Suppose you and a friend each take different random samples of data pairs (x, y) from the same population. Assume the samples are the same size. Based on your samples, you compute r = 0.83. Based on her sample, your friend computes r = 0.79. Is your friend’s value for r
Statistical Literacy Suppose that for x 5 3, the predicted value is yˆ 5
The data pair (3, 8) is part of the sample data. What is the value of the residual for x 5 3?
Desert Ecology: Wildlife Bighorn sheep are beautiful wild animals found throughout the western United States. Data for this problem are based on information taken from The Desert Bighorn, edited by Monson and Sumner(University of Arizona Press). Let x be the age of a bighorn sheep (in years), and
Sociology: Job Changes A sociologist is interested in the relation between x 5 number of job changes and y 5 annual salary (in thousands of dollars)for people living in the Nashville area. A random sample of 10 people employed in Nashville provided the following information:x (Number of job
Medical: Fat Babies Modern medical practice tells us not to encourage babies to become too fat. Is there a positive correlation between the weight x of a 1-year-old baby and the weight y of the mature adult (30 years old)? A random sample of medical fi les produced the following information for 14
Sales: Insurance Dorothy Kelly sells life insurance for the Prudence Insurance Company. She sells insurance by making visits to her clients’ homes. Dorothy believes that the number of sales should depend, to some degree, on the number of visits made. For the past several years, she has kept
Marketing: Coupons Each box of Healthy Crunch breakfast cereal contains a coupon entitling you to a free package of garden seeds. At the Healthy Crunch home offi ce, the weight of incoming mail is used to determine how many employees are to be assigned to collecting coupons and mailing out seed
Focus Problem: Changing Population and Crime Rate Let x be a random variable representing percentage change in neighborhood population in the past few years, and let y be a random variable representing crime rate(crimes per 1000 population). A random sample of six Denver neighborhoods gave the
Statistical Literacy List three methods of assigning probabilities.
Statistical Literacy Suppose the newspaper states that the probability of rain today is 30%. What is the complement of the event “rain today”? What is the probability of the complement?
Statistical Literacy What is the probability of(a) an event A that is certain to occur?(b) an event B that is impossible?
Statistical Literacy What is the law of large numbers? If you were using the relative frequency of an event to estimate the probability of the event, would it be better to use 100 trials or 500 trials? Explain.
Interpretation A Harris Poll indicated that of those adults who drive and have a cell phone, the probability that a driver between the ages of 18 and 24 sends or reads text messages is 0.51. Can this probability be applied to all drivers with cell phones? Explain.
Basic Computation: Probability as Relative Frequency A recent Harris Poll survey of 1010 U.S. adults selected at random showed that 627 consider the occupation of fi refi ghter to have very great prestige. Estimate the probability(to the nearest hundredth) that a U.S. adult selected at random
Basic Computation: Probability of Equally Likely Events What is the probability that a day of the week selected at random will be a Wednesday?
Interpretation An investment opportunity boasts that the chance of doubling your money in 3 years is 95%. However, when you research the details of the investment, you estimate that there is a 3% chance that you could lose the entire investment. Based on this information, are you certain to make
Interpretation A sample space consists of 4 simple events: A, B, C, D. Which events comprise the complement of A? Can the sample space be viewed as having two events, A and Ac? Explain.
Critical Thinking Consider a family with 3 children. Assume the probability that one child is a boy is 0.5 and the probability that one child is a girl is also 0.5, and that the events “boy” and “girl” are independent.(a) List the equally likely events for the gender of the 3 children, from
Critical Thinking Consider the experiment of tossing a fair coin 3 times. For each coin, the possible outcomes are heads or tails.(a) List the equally likely events of the sample space for the three tosses.(b) What is the probability that all three coins come up heads? Notice that the complement of
Showing 3500 - 3600
of 5564
First
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
Last
Step by Step Answers
Get 50% OFF
Claim Now
