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Chapter: 6 -Problem: 1 >> Examine Figure 6-37. Government documents and the Census Bureau show that the age at first marriage for U.S. citizens is approximately normally distributed for both men and women. For men, the average age is about 27 years, and for women, the average is about 24 years. For both sexes, the standard deviation is about 2.5 years. (a) If the distribution is symmetrical and mound-shaped (such as the no
Answer Preview: (a) If the distribution is symmetrical and mound-shaped (such as the normal distribution), you would expect the median, mean, and mode to be equal bec…

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, Chapter: 12 -Problem: 1 >> Discuss each of the following topics in class or review the topics on your own. Then write a brief but complete essay in which you summarize the main points. Please include formulas and graphs as appropriate. 1. (a) What do we mean by the term nonparametric statistics? What do we mean by the term parametric statistics? How do nonparametric methods differ from the methods we studied earlier? (b) Wh
Answer Preview: 1.(a) The term nonparametric means that no specific distribution is assumed to hold. Parametric mean…

, Chapter: 6 -Problem: 21 >> Instead of hearing the jingle of prices being rung up manually on cash registers, we now hear the beep of prices being scanned by electronic scanners. How accurate is price scanning? There are errors, and according to a Denver Post article, when the error occurs in the store’s favor, it is larger than when it occurs in the customer’s favor. An investigation of large discount stores by the Colorado
Answer Preview: (a) The 68% occurs because 68% of the locations are within tw…

, Chapter: 9 -Problem: 2 >> “Sweets May Not Be Culprit in Hyper Kids”—This is a USA Today headliner reporting results of a study that appeared in the New England Journal of Medicine. In this study, the subjects were 25 normal preschoolers, aged 3 to 5, and 23 kids, aged 6 to 10, who had been described as “sensitive to sugar.” The kids and their families were put on three different diets for 3 weeks each. One diet was high in
Answer Preview: (a) Some variables that might be measured to reflect the behavior of the children include…

, Chapter: 5 -Problem: 1 >> Powerball! Imagine, you could win a jackpot worth at least $10 million. Some jackpots have been worth more than $250 million! Powerball is a multistate lottery. To play Powerball, you purchase a $1 ticket. On the ticket you select five distinct white balls (numbered 1 through 55) and then one red Powerball (numbered 1 through 42). The red Powerball number may be any of the numbers 1 through 42, in
Answer Preview: (a) P(No Win) = P(No Prize) = 1/3328 = 0 00000046. (b) P(Win) = P(Jackpot) = 1/333 + 1/3328 + …

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, Chapter: 1 -Problem: 7 >> Make a statistical profile of your own statistics class. Items of interest might be (a) Height, age, gender, pulse, number of siblings, marital status (b) Number of college credit hours completed (as of beginning of term); grade point average (c) Major; number of credit hours enrolled in this term (d) Number of scheduled hours working per week (e) Distance from residence to first class; time it ta
Answer Preview: All the ticked ones are the correct ones ticked, except common sense rules should be stated for any …

, Chapter: 6 -Problem: 4 >> Can a normal distribution always be used to approximate a binomial distribution? Explain.
Answer Preview: No, a binomial distribution cannot always be approximated by a normal distri…

, Chapter: 9 -Problem: 1 >> “With Sampling, There Is Too a Free Lunch”—This is a headline that appeared in TheWall Street Journal. The article is about food product samples available at grocery stores. Giving out food samples is expensive and labor-intensive. It clogs supermarket aisles. It is risky. What if a customer tries an item and spits it out on the floor or says the product is awful? It creates litter. Some customers
Answer Preview: (a) I will use the null hypothesis that the percentage of customers who sample a product is less tha…

, Chapter: 6 -Problem: 24 >> How easy is it to contact a person in Sacramento, California? If you don’t know the telephone number, it could be difficult. The data from Survey Sampling of Fairfield, Connecticut, reported in American Demographics, show that 68% of the telephone-owning households in Sacramento have unlisted numbers. For a random sample of 150 Sacramento households with telephones, what is the probability that (a
Answer Preview: (a) 150 0 68 = 10…

, Chapter: 6 -Problem: 7 >> Given that z is the standard normal variable (with mean 0 and standard deviation 1), find(a) P(0 ? z ? 1.75) (b) P(– 1.29 ?  z ? 0) (c) P(1.03 ? z ? 1.21) (d) P(z ? 2.31) (e) P(z ? 1.96) (f ) P(z ? 1.00)
Answer Preview: (a) The probability that z = 0 or z = 1 75 is P(z 1 75) = 0 1849 or 18 49% (b) The …

, Chapter: 6 -Problem: 1 >> Describe a normal probability distribution.
Answer Preview: Normal distribution, also known as the Gaussian distribut…

, Chapter: 7 -Problem: 1 >> Break into small groups and discuss the following topics. Organize a brief outline in which you summarize the main points of your group discussion. Iris setosa is a beautiful wildflower that is found in such diverse places as Alaska, the Gulf of St. Lawrence, much of North America, and even in English meadows and parks. R. A. Fisher, with his colleague Dr. Edgar Anderson, studied these flowers ext
Answer Preview: (a) The group examined the histogram for petal lengths and concluded that the distribution appears to be approximately mound-shaped and symmetrical. T…

, Chapter: 6 -Problem: 8 >> Given that z is the standard normal variable (with mean 0 and standard deviation 1), find(a) P(0 ? z  ? 0.75) (b) P(– 1.50 ? z ? 0)(c) P(–2.67 ? z ? 1.74) (d) P(z ? 1.56) (e) P(z ?– 0.97) (f) P(z ? 2.01)
Answer Preview: (a) P(0 z 0 75) We have z = 0: P(0 z 0 75) = P(z 1 50) = P(1 50 z < 0) = 1 P(z > 1 50) = 1 e-0 75 .2…

, Chapter: 1 -Problem: 1 >> Use a random-number table or random-number generator to simulate tossing a fair coin 10 times. Generate 20 such simulations of 10 coin tosses. Compare the simulations. Are there any strings of 10 heads? of 4 heads? Does it seem that in most of the simulations half the outcomes are heads? half are tails? In Chapter 5, we will study the probabilities of getting from 0 to 10 heads in such a simulatio
Answer Preview: The number of total outcomes for tossing a fair coin …

, Chapter: 9 -Problem: 1 >> Discuss each of the following topics in class or review the topics on your own. Then write a brief but complete essay in which you summarize the main points. Please include formulas and graphs as appropriate. The most important questions in life usually cannot be answered with absolute certainty. Many important questions are answered by giving an estimate and a measure of confidence in the estimat
Answer Preview: Type I and Type II errors associated with hypothesis testing refer to mistakes made when deciding whether or not to reject the null hypothesis. A Type …

, Chapter: 1 -Problem: 1 >> Discuss each of the following topics in class or review the topics on your own. Then write a brief but complete essay in which you summarize the main points. Please include formulas and graphs as appropriate. 1. What does it mean to say that we are going to use a sample to draw an inference about a population? Why is a random sample so important for this process? If we wanted a random sample of st
Answer Preview: 1. It means that in order to estimate the population mean, we draw a r…

, Chapter: 8 -Problem: 2 >> Examine Figure 8-8, “Fall Back.” (a) Of the 1024 adults surveyed, 66% were reported to favor daylight saving time. How many people in the sample preferred daylight saving time? Using the statistic p? = 0.66 and sample size n = 1024, find a 95% confidence interval for the proportion of people p who favor daylight saving time. How could you report this information in terms of a margin of error? (b)
Answer Preview: a) 66% (or 0 66) of the adults surveyed in the sample favor daylight saving time, which equates to 6…

, Chapter: 6 -Problem: 2 >> Examine Figure 6-38, “Time Shopping.” (a) Notice that 52% of the people who go to a shopping center spend less than 1 hour. However, the figure also states that people spend an average of 69 minutes on each visit to a shopping center. How could both these claims be correct? Write a brief, complete essay in which you discuss mean, median, and mode in the context of a symmetrical distribution. Also
Answer Preview: (a) Mean, median, and mode are three different types of averages used to measure data sets. The mean, or average, is the sum of all the values divided …

, Chapter: 4 -Problem: 2 >> Consider the information given in Figure 4-12, “Vulnerable Knees.” What is the probability that an orthopedic case selected at random involves knee problems? Of those cases, estimate the probability that the case requires full knee replacement. Compute the probability that an orthopedic case selected at random involves a knee problem and requires a full knee replacement. Next, look at the probabil
Answer Preview: The probability that an orthopedic case selected at random involves knee problems is 0 …

, Chapter: 7 -Problem: 7 >> About 11% of Americans believe that Joan of Arc was Noah’s wife. (Source: Harper’s Index, Volume 3.) At a large freshman symposium, a college professor (jokingly) says that Joan of Arc was Noah’s wife. Assume that college freshmen are representative of the general American population regarding biblical knowledge. (a) If the symposium was attended by 55 freshmen, what is the probability that up to
Answer Preview: (a) Given: X is the number of students in the audience who believe Joan of Arc was Noahs wife. Solut…

, Chapter: 11 -Problem: 1 >> The Statistical Abstract of the United States reported information about the percentage of arrests of all drunk drivers according to age group. In the following table, the entry 3.7 in the first row means that in the entire United States, about 3.7% of all people arrested for drunk driving were in the age group 16–17 years. The Freemont County Sheriff’s Office obtained data about the number of dru
Answer Preview: a) Null Hypothesis: The age distribution of drunk drivers arrested in Freemont County is the same as …

, Chapter: 6 -Problem: 23 >> The Flight for Life emergency helicopter service is available for medical emergencies occurring from 15 to 90 miles from the hospital. Emergencies that occur closer to the hospital can be handled effectively by ambulance service. A long-term study of the service shows that the response time from receipt of the dispatch call to arrival at the scene of the emergency is normally distributed, with a m
Answer Preview: (a) The response time is normally distributed with a mean of 42 minutes and a standard deviation …

, Chapter: 2 -Problem: 1 >> Discuss each of the following topics in class or review the topics on your own. Then write a brief but complete essay in which you summarize the main points. Please include formulas and graphs as appropriate. 1. In your own words, explain the differences among histograms, relative-frequency histograms, bar graphs, circle graphs, time-series graphs, Pareto charts, and stem-and-leaf displays. If you
Answer Preview: Solution: 1. The graphic displays that might be useful is called a stem-and-leaf diagram. Sometimes it is called the tree or chart. The real name for …

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, Chapter: 6 -Problem: 1 >> Discuss each of the following topics in class or review the topics on your own. Then write a brief but complete essay in which you summarize the main points. Please include formulas and graphs as appropriate. 1. If you look up the word normal in a dictionary, you will find that it is synonymous with the words standard or usual. Consider the very wide and general applications of the normal probabil
Answer Preview: Solution: 1. The three random variables include: i) suitability of the selected distribution to the …

, Chapter: 6 -Problem: 13 >> Find z such that 95% of the area under the standard normal curve lies between –z and z.
Answer Preview: The area lies between z and z is 95% We find the corresponding …

, Chapter: 3 -Problem: 1 >> Discuss each of the following topics in class or review the topics on your own. Then write a brief but complete essay in which you summarize the main points. Please include formulas and graphs as appropriate. 1. An average is an attempt to summarize a collection of data into just one number. Discuss how the mean, median, and mode all represent averages in this context. Also discuss the differences
Answer Preview: Solution: 1. The three random variables include: i) Width, ii) Length, and iii) Area. Transform the …

, Chapter: 2 -Problem: 2 >> Examine Figure 2-21, “Global Teen Worries.” How many countries were contained in the sample? The graph contains bars and a circle. Which bar is the longest? Which bar represents the greatest percentage? Is this a bar graph or not? If not, what changes would need to be made to put the information into a bar graph? Could the graph be made into a Pareto chart? Could it be made into a circle graph? Ex
Answer Preview: 41 nations were represented in the sample, according to the graph. The worry bar for "getting a un…

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, Chapter: 7 -Problem: 1 >> Discuss each of the following topics in class, or review the topics on your own. Then write a brief but complete essay in which you summarize the main points. Please include formulas and graphs as appropriate. 1. Most people would agree that increased information should give better predictions. Discuss how sampling distributions actually enable better predictions by providing more information. Exa
Answer Preview: The central limit theorem states that as the sample …

, Chapter: 2 -Problem: 1 >> Examine Figure 2-20, “Everyone Agrees: Slobs Make Worst Roommates.” This is a clustered bar graph because two percentages are given for each response category: responses from men and responses from women. Comment about how the artistic rendition has slightly changed the format of a bar graph. Do the bars seem to have lengths that accurately reflect the relative percentages of the responses? In you
Answer Preview: The artistic rendition of this clustered bar graph has slightly changed the format of a bar graph in …

, Chapter: 8 -Problem: 1 >> Discuss each of the following topics in class or review the topics on your own. Then write a brief but complete essay in which you summarize the main points. Please include formulas and graphs as appropriate. 1. In this chapter, we have studied confidence intervals. Carefully read the following statements about confidence intervals: (a) Once the endpoints of the confidence interval are numerically
Answer Preview: a) The paper reported a point estimate of 78%, with margin of error of 3%. Write this information in the form of a confidence interval for p, the popu…

, Chapter: 8 -Problem: 1 >> Garrison Bay is a small bay in Washington state. A popular recreational activity in the bay is clam digging. For several years, this harvest has been monitored and the size distribution of clams recorded. Data for lengths and widths of little neck clams (Protothaca staminea) were recorded by a method of systematic sampling in a study done by S. Scherba and V. F. Gallucci (“The Application of Syste
Answer Preview: (a) To compute the sample mean and sample standard deviation for the lengths and widths and the coefficient of variation for each, we can use a calculator or statistical software. Using the data provi…

, Chapter: 1 -Problem: 2 >> Use a random-number table or random-number generator to generate a random sample of 30 distinct values from the set of integers from 1 to 100. Instructions for doing this using the TI-84Plus/TI-83Plus, Excel, Minitab, or SPSS are given in Using Technology at the end of this chapter. Generate five such samples. How many of the samples include the number 1? the number 100? Comment about the differen
Answer Preview: a. They are : 1,1,1,1,1,0,0,0,0. b. They are : 0,,2. c. They are spread unevenly. Some …

, Chapter: 3 -Problem: 1 >> The Story of Old Faithful is a short book written by George Marler and published by the Yellowstone Association. Chapter 7 of this interesting book talks about the effect of the 1959 earthquake on eruption intervals for Old Faithful Geyser. Dr. John Rinehart (a senior research scientist with the National Oceanic and Atmospheric Administration) has done extensive studies of the eruption intervals b
Answer Preview: Solution: My explanation is that the graph has many more eruptions of Old …

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, Chapter: 4 -Problem: 1 >> Discuss each of the following topics in class or review the topics on your own. Then write a brief but complete essay in which you summarize the main points. Please include formulas as appropriate. 1. Discuss the following concepts and give examples from everyday life in which you might encounter each concept. (a) Sample space. (b) Probability assignment to a sample space. In your discussion, be s
Answer Preview: (a) Sample space refers to the set of all possible outcomes of a random experiment. For example, if you roll a die, the sample space would be the set {1, 2, 3, 4, 5, 6}. In everyday life, you might en…

, Chapter: 1 -Problem: 8 >> Census and You, a publication of the Census Bureau, indicates that “Wherever your Web journey ends up, it should start at the Census Bureau’s site.” Visit the Brase/Brase statistics site at college.hmco.com/pic/braseUS9e and find a link to the Census Bureau’s site, as well as to Fedstats, another extensive site offering links to federal data. The Census Bureau site touts itself as the source of “o
Answer Preview: The above entails implementing a phased implementation of the census for each county and municipalit…

, Chapter: 10 -Problem: 1 >> Discuss each of the following topics in class or review the topics on your own. Then write a brief but complete essay in which you summarize the main points. Please include formulas and graphs as appropriate. 1. What do we mean when we say that two variables have a strong positive (or negative) linear correlation? What would a scatter diagram for these variables look like? Is it possible that two
Answer Preview: 1. When we say that two variables have a strong positive (or negative) linear correlation, we mean that they have a high correlation coefficient. The correlation coefficient is a measure of the streng…

, Chapter: 7 -Problem: 9 >> Suppose we have a binomial distribution with n trials and probability of success p. The random variable r is the number of successes in the n trials, and the random variable representing the proportion of successes is p? =  r/n. (a) n = 50; p = 0.22; Compute P(0.20 ? p? ? 0.25). (b) n = 38; p = 0.27; Compute the probability that p?  will equal or exceed 0.35. (c) n = 51; p = 0.05; Can we approxima
Answer Preview: We're supposed to use the normal approximation to a binomial to find the indicated probability. We are using a normal approximation to …

, Chapter: 5 -Problem: 1 >> Discuss each of the following topics in class or review the topics on your own. Then write a brief but complete essay in which you summarize the main points. Please include formulas and graphs as appropriate.1. Discuss what we mean by a binomial experiment. As you can see, a binomial process or binomial experiment involves a lot of assumptions! For example, all the trials are supposed to be indepe
Answer Preview: 1. A binomial experiment is a type of experiment that involves a fixed number of trials with a binary outcome, such as success or failure. Each trial is assumed to be independent of the others and the …

, Chapter: 8 -Problem: 3 >> Examine Figure 8-9,“Coupons: Limited Use.” (a) Use Figure 8-9 to estimate the percentage of merchandise coupons that were redeemed. Also estimate the percentage dollar value of the coupons that were redeemed. Are these numbers approximately equal? (b) Suppose you are a marketing executive working for a national chain of toy stores. You wish to estimate the percentage of coupons that will be redeem
Answer Preview: (a) The estimated percentage of merchandise coupons that were redeemed is 4 5/310 = 0 0145 or 1 45%. …

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, Chapter: 11 -Problem: 1 >> Discuss each of the following topics in class or review the topics on your own. Then write a brief but complete essay in which you summarize the main points. Please include formulas and graphs as appropriate. 1. In this chapter, you studied the chi-square distribution and three principal applications of the distribution. (a) Outline the basic ideas behind the chi-square test of independence. What
Answer Preview: (a) The chi-square test of independence is used to determine if there is a significant association between two categorical variables. A contingency table is a table that displays the frequency distrib…

, Chapter: 5 -Problem: 2 >> Would you like to travel in space, if given a chance? According to Opinion Research for Space Day Partners, if your answer is yes, you are not alone. Fortyfour percent of adults surveyed agreed that they would travel in space if given a chance. Look at Figure 5-8, and use the information presented to answer the following questions. (a) According to Figure 5-8, the probability that an adult selecte
Answer Preview: (a) Since the value of is 65%, using the binomial distributi…

, Chapter: 7 -Problem: 8 >> Thomas Myers is a staff physician at the clinic in Grand Canyon Village. Based on reports in recent years, Dr. Myers estimates that about 31% of the boating accidents on the Colorado River in Grand Canyon National Park occur at Crystal Rapids (mile 98). These range from small accidents (a few bruises) to major accidents (death). (a) What is the probability that at least 25% of these accidents occu
Answer Preview: (a) From the data in th…

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10 Reviews for Understandable Statistics Concepts And Methods Textbook Questions And Answers