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

Result Not Found

Books FREE
Study Help
Tutors
AI Study Planner NEW
Sell Books

Search
Sign In
Register

study help
mathematics
statistics

Introduction To Probability And Statistics 14th Edition William Mendenhall, Robert Beaver, Barbara Beaver - Solutions

Let x be a binomial random variable with n = 10 and p = .4. Find these values:a. P(x = 4)b. P(x ≥ 4)c. P(x > 4)d. P(x ≤ 4)e. µ = npf. σ = √npq
A West Coast university has found that about 90% of its accepted applicants for enrollment in the freshman class will actually enroll. In 2012, 1360 applicants were accepted to the university. Within what limits would you expect to find the size of the freshman class at this university in the fall
Suppose that one out of every 10 homeowners in the state of California has invested in earthquake insurance. If 15 homeowners are randomly chosen to be interviewed, a. What is the probability that at least one had earthquake insurance? b. What is the probability that four or more have earthquake
Improperly wired control panels were mistakenly installed on two of eight large automated machine tools. It is uncertain which of the machine tools have the defective panels, and a sample of four tools is randomly chosen for inspection. What is the probability that the sample will include no
How do you survive when there's no time to eat-fast food, no food, a protein bar, candy? A Snapshot in USA Today indicates that 36% of women aged 25-55 say that, when they are too busy to eat, they get fast food from a drive-thru. A random sample of 100 women aged 25-55 is selected.a. What is the
According to a USA Today Snapshot, drivers say fixing or repaving streets is the best way to make their communities drivable-better than building new roads or adding lanes. Suppose that n = 15 drivers are randomly selected and x is the number who say that improved road conditions would make their
The recession has caused many people to use their credit cards far less. In fact, in the United States, 60% of consumers say they are committed to living with fewer credit cards. A sample of n = 400 consumers with credit cards are randomly selected.a. What is the average number of consumers in the
A new surgical procedure is said to be successful 80% of the time. Suppose the operation is performed five times and the results are assumed to be independent of one another. What are the probabilities of these events? a. All five operations are successful. b. Exactly four are successful. c. Less
Refer to Exercise 5.96. If less than two operations were successful, how would you feel about the performance of the surgical team? Exercise 5.96 A new surgical procedure is said to be successful 80% of the time. Suppose the operation is performed five times and the results are assumed to be
Suppose the four engines of a commercial aircraft are arranged to operate independently and that the probability of in-flight failure of a single engine is .01. What is the probability of the following events on a given flight? a. No failures are observed. b. No more than one failure is observed.
Suppose that 50% of all young adults prefer McDonald's to Burger King when asked to state a preference. A group of 10 young adults were randomly selected and their preferences recorded. a. What is the probability that more than 6 preferred McDonald's? b. What is the probability that between 4 and 6
How safe is it to live near a nuclear reactor? Men who lived in a coastal strip that extends 20 miles north from a nuclear reactor in Plymouth, Massachusetts, developed some forms of cancer at a rate 50% higher than the statewide rate, according to a study endorsed by the Massachusetts Department
Consider a standard normal random variable with µ = 0 and standard deviation σ = 1. Use Table 3 to find the following probabilities: a. P(z < 2) b. P(z > 1.16) c. P(- 2.33 < z < 2.33) d. P(z < 1.88)
a. Find a z0 such that P(- z0 < z < z0) = .90. b. Find a z0 such that P(- z0 < z < z0) = .99.
Find the following percentiles for the standard normal random variable z: a. 90th percentile b. 95th percentile c. 98th percentile d. 99th percentile
A normal random variable x has mean µ = 10 and standard deviation σ = 2. Find the probability associated with each of the following intervals. a. x > 13.5 b. x = 8.2 c. 9.4 < x < 10.6
A normal random variable x has mean µ = 1.2 and standard deviation σ = .15. Find the probability associated with each of the following intervals. a. 1.00 < x < 1.10 b. x > 1.38 c. 1.35 < x < 1.50
A normal random variable x has an unknown mean m and standard deviation σ = 2. If the probability that x exceeds 7.5 is .8023, find µ.
A normal random variable x has mean 35 and standard deviation 10. Find a value of x that has area .01 to its right. This is the 99th percentile of this normal distribution.
A normal random variable x has mean 50 and standard deviation 15. Would it be unusual to observe the value x = 0? Explain your answer.
A normal random variable x has an unknown mean and standard deviation. The probability that x exceeds 4 is .9772, and the probability that x exceeds 5 is .9332. Find µ and σ.
The meat department at a local supermarket specifically prepares its "1-pound" packages of ground beef so that there will be a variety of weights, some slightly more and some slightly less than 1 pound. Suppose that the weights of these "1- pound" packages are normally distributed with a mean of
Human heights are one of many biological random variables that can be modeled by the normal distribution. Assume that the heights of American men have a mean of 69.5 inches and a standard deviation of 3.5 inches. a. What proportion of all men will be taller than 6'0"? b. What is the probability
Find these probabilities associated with the standard normal random variable z: a. P(z > 5) b. P(- 3 < z < 3) c. P(z < 2.81) d. P(z > 2.81)
The diameters of Douglas firs grown at a Christmas tree farm are normally distributed with a mean of 4 inches and a standard deviation of 1.5 inches. a. What proportion of the trees will have diameters between 3 and 5 inches? b. What proportion of the trees will have diameters less than 3
Cerebral blood flow (CBF) in the brains of healthy people is normally distributed with a mean of 74 and a standard deviation of 16. a. What proportion of healthy people will have CBF readings between 60 and 80? b. What proportion of healthy people will have CBF readings above 100? c. If a person
For a car traveling 30 miles per hour (mph), the distance required to brake to a stop is normally distributed with a mean of 50 feet and a standard deviation of 8 feet. Suppose you are traveling 30 mph in a residential area and a car moves abruptly into your path at a distance of 60 feet. a. If you
Suppose that you must establish regulations concerning the maximum number of people who can occupy an elevator. A study indicates that if eight people occupy the elevator, the probability distribution of the total weight of the eight people is approximately normally distributed with a mean equal to
The discharge of suspended solids from a phosphate mine is normally distributed, with a mean daily discharge of 27 milligrams per liter (mg/l) and a standard deviation of 14 mg/l. On what proportion of days will the daily discharge exceed 50 mg/l?
An experimenter publishing in the Annals of Botany investigated whether the stem diameters of the dicot sunflower would change depending on whether the plant was left to sway freely in the wind or was artificially supported. Suppose that the unsupported stem diameters at the base of a particular
The number of times x an adult human breathes per minute when at rest has a probability distribution that is approximately normal, with the mean equal to 16 and the standard deviation equal to 4. If a person is selected at random and the number x of breaths per minute while at rest is recorded,
One method of arriving at economic forecasts is to use a consensus approach. A forecast is obtained from each of a large number of analysts, and the average of these individual forecasts is the consensus forecast. Suppose the individual 2013 January prime interest rate forecasts of economic
How does the IRS decide on the percentage of income tax returns to audit for each state? Suppose they do it by randomly selecting 50 values from a normal distribution with a mean equal to 1.55% and a standard deviation equal to .45%. (Computer programs are available for this type of sampling.)a.
Suppose the numbers of a particular type of bacteria in samples of 1 milliliter (ml) of drinking water tend to be approximately normally distributed, with a mean of 85 and a standard deviation of 9. What is the probability that a given 1-ml sample will contain more than 100 bacteria?
Calculate the area under the standard normal curve to the left of these values: a. z = 1.6 b. z = 1.83 c. z = .90 d. z = 4.18
A grain loader can be set to discharge grain in amounts that are normally distributed, with mean m bushels and standard deviation equal to 25.7 bushels. If a company wishes to use the loader to fill containers that hold 2000 bushels of grain and wants to overfill only one container in 100, at what
A publisher has discovered that the number of words contained in new manuscripts is normally distributed, with a mean equal to 20,000 words in excess of that specified in the author's contract and a standard deviation of 10,000 words. If the publisher wants to be almost certain (say, with a
A stringer of tennis rackets has found that the actual string tension achieved for any individual racket will vary as much as 6 pounds per square inch from the desired tension set on the stringing machine. If the stringer wishes to string at a tension lower than that specified by a customer only 5%
An article in American Demographics claims that more than twice as many shoppers are out shopping on the weekends than during the week. Not only that, such shoppers also spend more money on their purchases on Saturdays and Sundays! Suppose that the amount of money spent at shopping centers between
What's a normal pulse rate? That depends on a variety of factors. Pulse rates between 60 and 100 beats per minute are considered normal for children over 10 and adults. Suppose that these pulse rates are approximately normally distributed with a mean of 78 and a standard deviation of 12. a. What
Consider a binomial random variable x with n = 25 and p = .6. a. Can the normal approximation be used to approximate probabilities in this case? Why or why not? b. What are the mean and standard deviation of x? c. Using the correction for continuity, approximate P(x > 9).
Consider a binomial random variable x with n = 45 and p = .05. a. Are np and nq both larger than 5? b. Based on your answer to part a, can we use the normal approximation to approximate the binomial probabilities associated with x? If not, is there another possible approximation we could use?
Let x be a binomial random variable with n = 25 and p = .3. a. Is the normal approximation appropriate for this binomial random variable? b. Find the mean and standard deviation for x. c. Use the normal approximation to find P(6 ≤ x ≤ 9). d. Use Table 1 in Appendix I to find the exact
Let x be a binomial random variable with n = 15 and p = .5.a. Is the normal approximation appropriate?b. Find P(x ≥ 6) using the normal approximation.c. Find P(x > 6) using the normal approximation.d. Find the exact probabilities for parts b and c, and compare these with your approximations.
Let x be a binomial random variable with n = 100 and p = .2. Find approximations to these probabilities: a. P(x > 22) b. P(x ≥ 22) c. P(20 < x < 25) d. P(x ≤ 25)
Calculate the area under the standard normal curve between these values: a. z = - 1.4 and z = 1.4 b. z = - 3.0 and z = 3.0
Let x be a binomial random variable with n = 25, p = .2. a. Use Table 1 in Appendix I to calculate P(4 ≤ x ≤ 6). b. Find µ and σ for the binomial probability distribution, and use the normal distribution to approximate the probability P(4 ≤ x ≤ 6). Note that this value is a good
Suppose the random variable x has a binomial distribution corresponding to n = 20 and p = .30. Use Table 1 of Appendix I to calculate these probabilities: a. P(x = 5) b. P(x ≥ 7)
Refer to Exercise 6.41. Use the normal approximation to calculate P(x = 5) and P(x ≥ 7). Compare with the exact values obtained from Table 1 in Appendix I.
Consider a binomial experiment with n = 20 and p = .4. Calculate P(x ≥ 10) using each of these methods: a. Table 1 in Appendix I b. The normal approximation to the binomial probability distribution
Find the normal approximation to P(355 ≤ x ≤ 360) for a binomial probability distribution with n = 400 and p = .9.
Are you helping to save the environment? A USA Today Snapshot found that about 78% of Americans believe that recycling trash makes the biggest difference in protecting the environment.Suppose a random sample of n = 50 adults are polled and asked if they believed that recycling made the biggest
Data collected over a long period of time show that a particular genetic defect occurs in 1 of every 1000 children. The records of a medical clinic show x = 60 children with the defect in a total of 50,000 examined. If the 50,000 children were a random sample from the population of children
Airlines and hotels often grant reservations in excess of capacity to minimize losses due to no-shows. Suppose the records of a hotel show that, on the average, 10% of their prospective guests will not claim their reservation. If the hotel accepts 215 reservations and there are only 200 rooms in
Compilation of large masses of data on lung cancer shows that approximately 1 of every 40 adults acquires the disease. Workers in a certain occupation are known to work in an air-polluted environment that may cause an increased rate of lung cancer. A random sample of n = 400 workers shows 19 with
Do Americans tend to vote for the taller of the two major candidates in a presidential election? In 49 of our presidential elections for which the heights of all the major-party candidates are known, 26 of the winners were taller than their opponents. Assume that Americans are not biased by a
Find the following probabilities for the standard normal random variable z: a. P(- 1.43 < z < .68) b. P(.58 < z < 1.74) c. P(- 1.55 < z < - .44) d. P(z > 1.34) e. P(z < - 4.32)
In a certain population, 15% of the people have Rh-negative blood. A blood bank serving this population receives 92 blood donors on a particular day. a. What is the probability that 10 or fewer are Rh-negative? b. What is the probability that 15 to 20 (inclusive) of the donors are Rh-negative? c.
Two of the biggest soft drink rivals, Pepsi and Coke, are very concerned about their market shares. The pie chart that follows claims that PepsiCo's share of the beverage market is 25%.6 Assume that this proportion will be close to the probability that a person selected at random indicates a
In a study conducted for the Center for a New American Dream, Time magazine reports that 60% of Americans felt pressure to work too much, and 80% wished for more family time.7 Assume that these percentages are correct for all Americans, and that a random sample of 25 Americans is selected. a. Use
The article in Time magazine7 (Exercise 6.52) also reported that 80% of men and 62% of women put in more than 40 hours a week on the job. Assume that these percentages are correct for all Americans, and that a random sample of 50 working women is selected. a. What is the average number of women who
Calculate the area under the standard normal curve to the left of these values: a. z = - .90 b. z = 2.34 c. z = 5.4
Calculate the area under the standard normal curve between these values: a. z = - 2.0 and z = 2.0 b. z = - 2.3 and z = - 1.5
Find the following probabilities for the standard normal random variable z: a. P(- 1.96 ≤ z ≤ 1.96) b. P(z >1.96) c. P(z < - 1.96)
a. Find a z0 such that P(z > z0) = .9750. b. Find a z0 such that P(z > z0) = .3594.
a. Find a z0 such that P(- z0 ≤ z ≤ z0) = .95. b. Find a z0 such that P(- z0 ≤ z ≤ z0) = .98. c. Find a z0 such that P(- z0 ≤ z ≤ z0) = .90. d. Find a z0 such that P(- z0 ≤ z ≤ z0) = .99.
A normal random variable x has mean µ = 5 and standard deviation σ = 2. Find the probabilities associated with the following intervals: a. 1.2 < x < 10 b. x > 7.5 c. x ≤ 0
Find these probabilities for the standard normal random variable z:a. P(z < 2.33)b. P(z < 1.645)c. P(z > 1.96)d. P(- 2.58 < z < 2.58)
Let x be a binomial random variable with n = 36 and p = .54. Use the normal approximation to find: a. P(x ≤ 25) b. P(15 ≤ x ≤ 20) c. P(x > 30)
Using Table 3 in Appendix I, calculate the area under the standard normal curve to the left of the following: a. z = 1.2 b. z = - .9 c. z = 1.46 d. z = - .42
Find the following probabilities for the standard normal random variable: a. P(.3 < z < 1.56) b. P(- .2 < z < .2)
Find z0 such that P(z > z0) = .5.
Find z0 such that P(- z0 < z < z0) = .5. What percentiles do - z0 and z0 represent?
It is estimated that the mean life span of oil-drilling bits is 75 hours. Suppose an oil exploration company purchases drill bits that have a life span that is approximately normally distributed with a mean equal to 75 hours and a standard deviation equal to 12 hours. a. What proportion of the
The influx of new ideas into a college or university, introduced primarily by new young faculty, is becoming a matter of concern because of the increasing ages of faculty members. That is, the distribution of faculty ages is shifting upward; there is a shortage of vacant positions and an oversupply
A machine operation produces bearings whose diameters are normally distributed, with mean and standard deviation equal to .498 and .002, respectively. If specifications require that the bearing diameter equal .500 inch ± .004 inch, what fraction of the production will be unacceptable?
a. Find a z0 such that P(z > z0) = .025. b. Find a z0 such that P(z < z0) = .9251.
A used-car dealership has found that the length of time before a major repair is required on the cars it sells is normally distributed with a mean equal to 10 months and a standard deviation of 3 months. If the dealer wants only 5% of the cars to fail before the end of the guarantee period, for how
The daily sales total (excepting Saturday) at a small restaurant has a probability distribution that is approximately normal, with a mean µ equal to $1230 per day and a standard deviation σ equal to $120. a. What is the probability that the sales will exceed $1400 for a given day? b. The
The life span of a type of automatic washer is approximately normally distributed with mean and standard deviation equal to 10.5 and 3.0 years, respectively. If this type of washer is guaranteed for a period of 5 years, what fraction will need to be repaired and/or replaced?
Most users of automatic garage door openers activate their openers at distances that are normally distributed with a mean of 30 feet and a standard deviation of 11 feet. To minimize interference with other remote-controlled devices, the manufacturer is required to limit the operating distance to 50
The average length of time required to complete a college achievement test was found to equal 70 minutes with a standard deviation of 12 minutes. When should the test be terminated if you wish to allow sufficient time for 90% of the students to complete the test? (Assume that the time required to
The length of time required to run a 5000-mile check and to service an automobile has a mean equal to 1.4 hours and a standard deviation of .7 hour. Suppose that the service department plans to service 50 automobiles per 8-hour day and that, in order to do so, it must spend no more than an average
An advertising agency has stated that 20% of all television viewers watch a given program. In a random sample of 1000 viewers, x = 184 viewers were watching the program. Do these data present sufficient evidence to contradict the advertiser's claim?
A researcher notes that senior corporation executives are not very accurate forecasters of their own annual earnings. He states that his studies of a large number of company executive forecasts "showed that the average estimate missed the mark by 15%." a. Suppose the distribution of these forecast
A soft drink machine can be regulated to discharge an average of µ ounces per cup. If the ounces of fill are normally distributed, with standard deviation equal to .3 ounce, give the setting for µ so that 8-ounce cups will overflow only 1% of the time.
A manufacturing plant uses light bulbs whose life spans are normally distributed, with mean and standard deviation equal to 500 and 50 hours, respectively. In order to minimize the number of bulbs that burn out during operating hours, all the bulbs are replaced after a given period of operation.
Find a z0 such that P(- z0 < z < z0) = .8262.
The admissions office of a small college is asked to accept deposits from a number of qualified prospective freshmen so that, with probability about .95, the size of the freshman class will be less than or equal to 120. Suppose the applicants constitute a random sample from a population of
An airline finds that 5% of the persons making reservations on a certain flight will not show up for the flight. If the airline sells 160 tickets for a flight that has only 155 seats, what is the probability that a seat will be available for every person holding a reservation and planning to fly?
It is known that 30% of all calls coming into a telephone exchange are long-distance calls. If 200 calls come into the exchange, what is the probability that at least 50 will be long-distance calls?
In Exercise 5.75, a cross between two peony plants-one with red petals and one with streaky petals-produced offspring plants with red petals 75% of the time. Suppose that 100 seeds from this cross were collected and germinated, and x, the number of plants with red petals, was recorded.a. What is
A purchaser of electric relays buys from two suppliers, A and B. Supplier A supplies two of every three relays used by the company. If 75 relays are selected at random from those in use by the company, find the probability that at most 48 of these relays come from supplier A. Assume that the
Psychologists believe that excessive eating may be associated with emotional states (being upset or bored) and environmental cues (watching television, reading, and so on). To test this theory, suppose you randomly selected 60 persons and matched them by weight and gender in pairs. For a period of
The Biology Data Book reports that the gestation time for human babies averages 278 days with a standard deviation of 12 days. Suppose that these gestation times are normally distributed. a. Find the upper and lower quartiles for the gestation times. b. Would it be unusual to deliver a baby after
In Exercise 6.28, we suggested that the IRS assigns auditing rates per state by randomly selecting 50 auditing percentages from a normal distribution with a mean equal to 1.55% and a standard deviation of .45%. a. What is the probability that a particular state would have more than 2% of its tax
Among the 10 most popular sports, men include competition-type sports-pool and billiards, basketball, and softball-whereas women include aerobics, running, hiking, and calisthenics. However, the top recreational activity for men was still the relaxing sport of fishing, with 41% of those surveyed
A psychological introvert-extrovert test produced scores that had a normal distribution with a mean and standard deviation of 75 and 12, respectively. If we wish to designate the highest 15% as extroverts, what would be the proper score to choose as the cutoff point?
a. Find a z0 that has area .9505 to its left. b. Find a z0 that has area .05 to its left.
The chest measurements for 5738 Scottish militiamen in the early 19th century are given below. Chest sizes are measured in inches, and each observation reports the number of soldiers with that chest size.Notice the approximate normality of the histogram of the 5738 chest measurements.a. The mean of

Showing 65000 - 65100 of 88243

First
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
Last

Step by Step Answers

Services

Sitemap
Fun
Definitions
Become Tutor
Used Textbooks
Study Help Categories
Recent Questions
Expert Questions
Campus Wear
Sell Your Books

Company Info

Security
Copyrights
Privacy Policy
Terms & Conditions
SolutionInn Fee
Scholarship
Online Quiz
Give Feedback, Get Rewards

Get In Touch

About Us
Contact Us
Career
Jobs
FAQ
Student Discount
Campus Ambassador

Secure Payment

Download Our App

© 2026 SolutionInn. All Rights Reserved