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
intro stats
Stats Data And Models (Subscription) 3rd Edition Richard D De Veaux, Paul D Velleman, David E Bock - Solutions
it is striped?b) If you pick three M&M’s in a row, what is the probability that
it is not green?
it is yellow or orange?
it is brown?
M&M’s. The Masterfoods company says that before the introduction of purple, yellow candies made up 20% of their plain M&M’s, red another 20%, and orange, blue, and green each made up 10%. The rest were brown.a) If you pick an M&M at random, what is the probability that
Polling, part II. According to Pew Research, the contact rate (probability of contacting a selected household) was 69% in 1997 and 76% in 2003. However, the cooperation rate (probability of someone at the contacted household agreeing to be interviewed) was 58% in 1997 and dropped to 38% in 2003.a)
Polling. As mentioned in the chapter, opinion-polling organizations contact their respondents by sampling random telephone numbers. Although interviewers now can reach about 76% of U.S. households, the percentage of those contacted who agree to cooperate with the survey has fallen from 58% in 1997
If we select two people at random from this sample,a) what is the probability that both think fathers are better today?b) what is the probability that neither thinks fathers are better today?c) what is the probability that one person thinks fathers are better today and the other doesn’t?d) What
Fathers, revisited. Consider again the results of the poll about fathering discussed in Exercise
More energy. Exercise 25 shows the results of a Gallup Poll about energy. Suppose we select three people at random from this sample.a) What is the probability that all three responded“Protect the environment”?b) What is the probability that none responded “Equally important”?c) What
Failing fathers? A Pew Research poll in 2007 asked 2020 U.S. adults whether fathers today were doing as good a job of fathering as fathers of 20–30 years ago.Here’s how they responded:If we select a respondent at random from this sample of 2020 adults,a) what is the probability that the
Energy 2007. A Gallup Poll in March 2007 asked 1005 U.S. adults whether increasing domestic energy production or protecting the environment should be given a higher priority. Here are the results:If we select a person at random from this sample of 1005 adults,a) what is the probability that the
Final project. You used the Multiplication Rule to calculate probabilities about the Calculus background of your Statistics groupmates in Exercise 22.a) What must be true about the groups in order to make that approach valid?b) Do you think this assumption is reasonable? Explain.
Repairs, again. You used the Multiplication Rule to calculate repair probabilities for your cars in Exercise 21.a) What must be true about your cars in order to make that approach valid?b) Do you think this assumption is reasonable? Explain.
What is the probability that of your other two groupmates,a) neither has studied Calculus?b) both have studied at least one semester of Calculus?c) at least one has had more than one semester of Calculus?
Another project. You are assigned to be part of a group of three students from the Intro Stats class described in Exercise
If you own two cars, what is the probability thata) neither will need repair?b) both will need repair?c) at least one car will need repair?
More repairs. Consider again the auto repair rates described in Exercise
Stats projects. In a large Introductory Statistics lecture hall, the professor reports that 55% of the students enrolled have never taken a Calculus course, 32% have taken only one semester of Calculus, and the rest have taken two or more semesters of Calculus. The professor randomly assigns
Car repairs. A consumer organization estimates that over a 1-year period 17% of cars will need to be repaired once, 7% will need repairs twice, and 4% will require three or more repairs. What is the probability that a car chosen at random will needa) no repairs?b) no more than one repair?c) some
College admissions II. In Exercise 17, we saw that in 2007 Harvard accepted about 9% of its applicants, Stanford 10%, and Penn 16%. Jorge has applied to all three. He figures that his chances of getting into at least one of the three must be about 35%.a) How has he arrived at this conclusion?b)
College admissions. For high school students graduating in 2007, college admissions to the nation’s most selective schools were the most competitive in memory (The New York Times, “A Great Year for Ivy League Schools, but Not So Good for Applicants to Them,” April 4, 2007). Harvard accepted
Lefties. Although it’s hard to be definitive in classifying people as right- or left-handed, some studies suggest that about 14% of people are left-handed. Since the Multiplication Rule might suggest that there’s about a 2% chance that a brother and a sister are both lefties. What’s wrong
Speeders. Traffic checks on a certain section of highway suggest that 60% of drivers are speeding there. Since the Multiplication Rule might suggest that there’s a 36% chance that two vehicles in a row are both speeding. What’s wrong with that reasoning?
Homes. Funding for many schools comes from taxes based on assessed values of local properties. People’s homes are assessed higher if they have extra features such as garages and swimming pools. Assessment records in a certain school district indicate that 37% of the homes have garages and 3% have
Vehicles. Suppose that 46% of families living in a certain county own a car and 18% own an SUV. The Addition Rule might suggest, then, that 64% of families own either a car or an SUV. What’s wrong with that reasoning?
Scratch off. Many stores run “secret sales”: Shoppers receive cards that determine how large a discount they get, but the percentage is revealed by scratching off that black stuff (what is that?) only after the purchase has been totaled at the cash register. The store is required to reveal (in
Spinner. The plastic arrow on a spinner for a child’s game stops rotating to point at a color that will determine what happens next. Which of the following probability assignments are possible? Probabilities of... Red Yellow Green Green Blue a) 0.25 0.25 0.25 0.25 b) 0.10 0.20 0.30 0.40 c) 0.20
Jackpot. On January 20, 2000, the International Gaming Technology company issued a press release:(LAS VEGAS, Nev.)—Cynthia Jay was smiling ear to ear as she walked into the news conference at The Desert Inn Resort in Las Vegas today, and well she should. Last night, the 37-year-old cocktail
Fire insurance. Insurance companies collect annual payments from homeowners in exchange for paying to rebuild houses that burn down.a) Why should you be reluctant to accept a $300 payment from your neighbor to replace his house should it burn down during the coming year?b) Why can the insurance
Crash. Commercial airplanes have an excellent safety record. Nevertheless, there are crashes occasionally, with the loss of many lives. In the weeks following a crash, airlines often report a drop in the number of passengers, probably because people are afraid to risk flying.a) A travel agent
Cold streak. A batter who had failed to get a hit in seven consecutive times at bat then hits a game-winning home run. When talking to reporters afterward, he says he was very confident that last time at bat because he knew he was “due for a hit.” Comment on his reasoning.
Snow. After an unusually dry autumn, a radio announcer is heard to say, “Watch out! We’ll pay for these sunny days later on this winter.” Explain what he’s trying to say, and comment on the validity of his reasoning.
Winter. Comment on the following quotation:“What I think is our best determination is it will be a colder than normal winter,” said Pamela Naber Knox, a Wisconsin state climatologist. “I’m basing that on a couple of different things. First, in looking at the past few winters, there has been
Rain. The weather reporter on TV makes predictions such as a 25% chance of rain. What do you think is the meaning of such a phrase?
Roulette. A casino claims that its roulette wheel is truly random. What should that claim mean?
Sample spaces. For each of the following, list the sample space and tell whether you think the events are equally likely:a) Roll two dice; record the sum of the numbers.b) A family has 3 children; record each child’s sex in order of birth.c) Toss four coins; record the number of tails.d) Toss a
Sample spaces. For each of the following, list the sample space and tell whether you think the events are equally likely:a) Toss 2 coins; record the order of heads and tails.b) A family has 3 children; record the number of boys.c) Flip a coin until you get a head or 3 consecutive tails;record each
The back nine. Use simulations to estimate more golf scores, similar to the procedure in Exercise 43.a) On a par 3, the golfer hopes the tee shot lands on the green. Assume that the tee shot behaves like the first approach shot described in Exercise 43.b) On a par 5, the second shot will reach the
In theory, a golfer playing a par-4 hole tees off, hitting the ball in the fairway, then hits an approach shot onto the green. The first putt (usually long) probably won’t go in, but the second putt (usually much shorter)should. Sounds simple enough, but how many strokes might it really take? Use
Par
Profiling? Among the 20 first-class passengers on the flight described in Exercise 41, there were four businessmen from the Middle East. Two of them were the two passengers selected to be searched. They complained of profiling, but the airline claims that the selection was random. What do you
Security. There are 20 first-class passengers and 120 coach passengers scheduled on a flight. In addition to the usual security screening, 10% of the passengers will be subjected to a more complete search.a) Describe a sampling strategy to randomly select those to be searched.b) Here is the
NBA draft lottery. Professional basketball teams hold a“draft” each year in which they get to pick the best available college and high school players. In an effort to promote competition, teams with the worst records get to pick first, theoretically allowing them to add better players.To combat
Knees. Research reported in the spring of 2002 cast doubt on the effectiveness of arthroscopic knee surgery for patients with arthritis. Patients suffering from arthritis pain who volunteered to participate in the study were randomly divided into groups. One group received arthroscopic knee
Bats. It’s generally believed that baseball players can hit the ball farther with aluminum bats than with the traditional wooden ones. Is that true? And, if so, how much farther? Players on your local high school baseball team have agreed to help you find out. Design an appropriate experiment.
Save the grapes. Vineyard owners have problems with birds that like to eat the ripening grapes. Some vineyards use scarecrows to try to keep birds away. Others use netting that covers the plants. Owners really would like to know if either method works and, if so, which one is better. One owner has
Bias? Political analyst Michael Barone has written that“conservatives are more likely than others to refuse to respond to polls, particularly those polls taken by media outlets that conservatives consider biased” (The Weekly Standard, March 10, 1997). The Pew Research Foundation tested this
Age and party. The Gallup Poll conducted a representative telephone survey during the first quarter of 1999.Among its reported results was the following table concerning the preferred political party affiliation of respondents and their ages:a) What sampling strategy do you think the pollsters
Pubs. In England, a Leeds University researcher said that the local watering hole’s welcoming atmosphere helps men get rid of the stresses of modern life and is vital for their psychological well-being. Author of the report, Dr. Colin Gill, said rather than complain, women should encourage men to
Sex and violence. Does the content of a television program affect viewers’ memory of the products advertised in commercials? Design an experiment to compare the ability of viewers to recall brand names of items featured in commercials during programs with violent content, sexual content, or
Antacids. A researcher wants to compare the performance of three types of antacid in volunteers suffering from acid reflux disease. Because men and women may react differently to this medication, the subjects are split into two groups, by sex. Subjects in each group are randomly assigned to take
Smoking and Alzheimer’s. Medical studies indicate that smokers are less likely to develop Alzheimer’s disease than people who never smoked.a) Does this prove that smoking may offer some protection against Alzheimer’s? Explain.b) Offer an alternative explanation for this association.c) How
Youthful appearance. Readers’ Digest reported results of several surveys that asked graduate students to examine photographs of men and women and try to guess their ages. Researchers compared these guesses with the number of times the people in the pictures reported having sexual intercourse. It
Homecoming. A college Statistics class conducted a survey concerning community attitudes about the college’s large homecoming celebration. That survey drew its sample in the following manner: Telephone numbers were generated at random by selecting one of the local telephone exchanges (first three
Rivets. A company that manufactures rivets believes the shear strength of the rivets they manufacture follows a Normal model with a mean breaking strength of 950 pounds and a standard deviation of 40 pounds.a) What percentage of rivets selected at random will break when tested under a 900-pound
When to stop? You play a game that involves rolling a die. You can roll as many times as you want, and your score is the total for all the rolls. But . . . if you roll a 6 your score is 0 and your turn is over. What might be a good strategy for a game like this?a) One of your opponents decides to
Laundry. An experiment to test a new laundry detergent, SparkleKleen, is being conducted by a consumer advocate group. They would like to compare its performance with that of a laboratory standard detergent they have used in previous experiments. They can stain 16 swatches of cloth with 2 tsp of a
Cloning. In September 1998, USAWeekend magazine asked, “Should humans be cloned?” Readers were invited to vote “Yes” or “No” by calling one of two different 900 numbers. Based on 38,023 responses, the magazine reported that “9 out of 10 readers oppose cloning.”a) Explain why you
In another experiment to see if getting candy after a meal would induce customers to leave a bigger tip, a waitress randomly decided what to do with 80 dining parties. Some parties received no candy, some just one piece, and some two pieces. Others initially got just one piece of candy, and then
Tips, take
Tips. In restaurants, servers rely on tips as a major source of income. Does serving candy after the meal produce larger tips? To find out, two waiters determined randomly whether or not to give candy to 92 dining parties.They recorded the sizes of the tips and reported that guests getting candy
Cell phone risks. Researchers at the Washington University School of Medicine randomly placed 480 rats into one of three chambers containing radio antennas. One group was exposed to digital cell phone radio waves, the second to analog cell phone waves, and the third group to no radio waves. Two
Everyday randomness. Aside from casinos, lotteries, and games, there are other situations you encounter in which something is described as “random” in some way.Give three different examples. Describe how randomness is (or is not) achieved in each.
You bet on three numbers. The state picks five winning numbers. If your three are all among the winners, you are rich!a) Simulate repeated plays. How long did it take you to win?b) In real lotteries, there are many more choices (often 54)and you must match all five winning numbers. Explain how
The lottery. Many people spend a lot of money trying to win huge jackpots in state lotteries. Let’s play a simplified version using only the numbers from 1 to
Point spread. When taking bets on sporting events, bookmakers often include a “point spread” that awards the weaker team extra points. In theory this makes the outcome of the bet a toss-up. Suppose a gambler places a$10 bet and picks the winners of five games. If he’s right about fewer than
Does the use of computer software in Introductory Statistics classes lead to better understanding of the concepts? Aprofessor teaching two sections of Statistics decides to investigate. She teaches both sections using the same lectures and assignments, but gives one class statistics software to
Physically fit people seem less likely to die of cancer.A report in the May 2002 issue of Medicine and Science in Sports and Exercise followed 25,892 men aged 30 to 87 for 10 years. The most physically fit men had a 55% lower risk of death from cancer than the least fit group.
A soft-drink manufacturer must be sure the bottle caps on the soda are fully sealed and will not come off easily.Inspectors pull a few bottles off the production line at regular intervals and test the caps. If they detect any problems, they will stop the bottling process to adjust or repair the
An orange-juice processing plant will accept a shipment of fruit only after several hundred oranges selected from various locations within the truck are carefully inspected.If too many show signs of unsuitability for juice (bruised, rotten, unripe, etc.), the whole truckload is rejected.
Researchers at the University of Bristol (England) investigated reasons why different species of birds begin to sing at different times in the morning. They captured and examined birds of 57 species at seven different sites.They measured the diameter of the birds’ eyes and also recorded the time
Tests of gene therapy on laboratory rats have raised hopes of stopping the degeneration of tissue that characterizes chronic heart failure. Researchers at the University of California, San Diego, used hamsters with cardiac disease, randomly assigning 30 to receive the gene therapy and leaving the
An artisan wants to create pottery that has the appearance of age. He prepares several samples of clay with four different glazes and test fires them in a kiln at three different temperature settings.
Researchers investigating appetite control as a means of losing weight found that female rats ate less and lost weight after injections of the hormone leptin, while male rats responded better to insulin. (Science News, July 20, 2002)
Some doctors have expressed concern that men who have vasectomies seemed more likely to develop prostate cancer. Medical researchers used a national cancer registry to identify 923 men who had had prostate cancer and 1224 men of similar ages who had not. Roughly one quarter of the men in each group
Can long-term exposure to strong electromagnetic fields cause cancer? Researchers in Italy tracked down 13 years of medical records for people living near Vatican Radio’s powerful broadcast antennas. A disproportionate share of the leukemia cases occurred among men and children who lived within 6
Can makeup damage fetal development? Many cosmetics contain a class of chemicals called phthalates. Studies that exposed some laboratory animals to these chemicals found a heightened incidence of damage to male reproductive systems. Since traces of phthalates are found in the urine of women who use
Fireworks manufacturers face a dilemma. They must be sure that the rockets work properly, but test-firing a rocket essentially destroys it. On the other hand, not testing the product leaves open the danger that they sell a bunch of duds, leading to unhappy customers and loss of future sales. The
In the journal Science, a research team reported that plants in southern England are flowering earlier in the spring.Records of the first flowering dates for 385 species over a period of 47 years indicate that flowering has advanced an average of 15 days per decade, an indication of climate
Almost 90,000 women participated in a 16-year study of the role of the vitamin folate in preventing colon cancer.Some of the women had family histories of colon cancer in close relatives. In this at-risk group, the incidence of colon cancer was cut in half among those who maintained a high folate
The radioactive gas radon, found in some homes, poses a health risk to residents. To assess the level of contamination in their area, a county health department wants to test a few homes. If the risk seems high, they will publicize the results to emphasize the need for home testing. Officials plan
Researchers at the Purina Pet Institute studied Labrador retrievers for evidence of a relationship between diet and longevity. At 8 weeks of age, 2 puppies of the same sex and weight were randomly assigned to one of two groups—a total of 48 dogs in all. One group was allowed to eat all they
The journal Circulation reported that among 1900 people who had heart attacks, those who drank an average of 19 cups of tea a week were 44% more likely than nondrinkers to survive at least 3 years after the attack.
Researchers identified 242 children in the Cleveland area who had been born prematurely (at about 29 weeks).They examined these children at age 8 and again at age 20, comparing them to another group of 233 children not born prematurely. Their report, published in the New England Journal of
Skydiving, anyone? A humor piece published in the British Medical Journal (“Parachute use to prevent death and major trauma related to gravitational challenge:Systematic review of randomized control trials,” Gordon, Smith, and Pell, BMJ, 2003:327) notes that we can’t tell for sure whether
Washing clothes. A consumer group wants to test the effectiveness of a new “organic” laundry detergent and make recommendations to customers about how to best use the product. They intentionally get grass stains on 30 white T-shirts in order to see how well the detergent will clean them. They
Safety switch. An industrial machine requires an emergency shutoff switch that must be designed so that it can be easily operated with either hand. Design an experiment to find out whether workers will be able to deactivate the machine as quickly with their left hands as with their right hands. Be
SAT prep. Can special study courses actually help raise SAT scores? One organization says that the 30 students they tutored achieved an average gain of 60 points when they retook the test.a) Explain why this does not necessarily prove that the special course caused the scores to go up.b) Propose a
Beetles. Hoping to learn how to control crop damage by a certain species of beetle, a researcher plans to test two different pesticides in small plots of corn. A few days after application of the chemicals, he’ll check the number of beetle larvae found on each plant. The researcher wants to know
Shingles. Aresearch doctor has discovered a new ointment that she believes will be more effective than the current medication in the treatment of shingles (a painful skin rash). Eight patients have volunteered to participate in the initial trials of this ointment. You are the statistician hired as
Weekend deaths. A study published in the New England Journal of Medicine (Aug. 2001) suggests that it’s dangerous to enter a hospital on a weekend. During a 10-year period, researchers tracked over 4 million emergency admissions to hospitals in Ontario, Canada.Their findings revealed that
Gas mileage. Do cars get better gas mileage with premium instead of regular unleaded gasoline? It might be possible to test some engines in a laboratory, but we’d rather use real cars and real drivers in real day-to-day driving, so we get 20 volunteers. Design the experiment.
Reading. Some schools teach reading using phonics(the sounds made by letters) and others using whole language (word recognition). Suppose a school district wants to know which method works better. Suggest a design for an appropriate experiment.
Healing. A medical researcher suspects that giving postsurgical patients large doses of vitamin E will speed their recovery times by helping their incisions heal more quickly. Design an experiment to test this conjecture. Be sure to identify the factors, levels, treatments, response variable, and
Dowsing. Before drilling for water, many rural homeowners hire a dowser (a person who claims to be able to sense the presence of underground water using a forked stick.)Suppose we wish to set up an experiment to test one dowser’s ability. We get 20 identical containers, fill some with water, and
Swimming. Recently, a group of adults who swim regularly for exercise were evaluated for depression. It turned out that these swimmers were less likely to be depressed than the general population. The researchers said the difference was statistically significant.a) What does “statistically
Wine. A 2001 Danish study published in the Archives of Internal Medicine casts significant doubt on suggestions that adults who drink wine have higher levels of “good”cholesterol and fewer heart attacks. These researchers followed a group of individuals born at a Copenhagen hospital between
Contrast bath treatments use the immersion of an injured limb alternately in water of two contrasting temperatures.Those who use the method claim that it can reduce swelling. Researchers compared three treatments: (1) contrast baths and exercise, (2) contrast baths alone, and(3) exercise alone. (R.
Mozart. Will listening to a Mozart piano sonata make you smarter? In a 1995 study published in the journal Psychological Science, Rauscher, Shaw, and Ky reported that when students were given a spatial reasoning section of a standard IQ test, those who listened to Mozart for 10 minutes improved
Showing 5000 - 5100
of 5937
First
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
Last
Step by Step Answers
Get 50% OFF
Claim Now
