Most popular questions
  1. statistics

    the life spans of three randomly selected tires are 31,400 miles, 40,600 miles and 36,000 miles. Using the empirical rule, find the percentile that corresponds to each life span.

    asked by cynthia on September 8, 2013
  2. statistics

    Customers arrive at a movie theater at the advertised movie time only to find that they have to sit through several previews and prepreview ads before the movie starts. Many complain that the time devoted to previews is too long (The Wall Street Journal,

    asked by sean on November 16, 2014
  3. Statistics

    One of the questions in the Pew Internet & American Life Project asked adults if they used the Internet, at least occasionally. The results showed that 454 out of 478 adults aged 18 - 29 answered yes; 741 out of 833 adults aged 30 – 49 answered yes; 1058

    asked by Jen on June 16, 2014
  4. statistics

    According to a college survey, 22% of all students work full time. Find the mean and standard deviation for the number of students who work full time in samples of size 16.

    asked by Hannah on March 16, 2015
  5. statistics

    A tennis player makes a successful first serve 51% of the time. if she serves 9 times, what is the probability that she gets exactly 3 first serves in? assume that each serve is independent of the others.

    asked by Anonymous on April 15, 2015
  6. Statistics

    The mean cost of domestic airfares in the United States rose to an all-time high of $385 per ticket. Airfares were based on the total ticket value, which consisted of the price charged by the airlines plus any additional taxes and fees. Assume domestic

    asked by Sam on June 11, 2014
  7. statistics

    In the game of​ roulette, a wheel consists of 38 slots numbered​ 0, 00,​ 1, 2,..., 36. To play the​ game, a metal ball is spun around the wheel and is allowed to fall into one of the numbered slots. If the number of the slot the ball falls into

    asked by A on October 11, 2017
  8. statistics

    In a batch of 8,000 clock radios 5% are defective. A sample of 14 clock radios is randomly selected without replacement from the 8,000 and tested. The entire batch will be rejected if at least one of those tested is defective. What is the probability that

    asked by havier on July 21, 2014
  9. Statistics

    1) A null Hypothesis assumes that a process is producing no more than a maximum allowable rate of defective items. The Type II error is to conclude that the process? 2) If 95% confidence limits for the mean Mu turn out to be (6.5,8.5)

    asked by Frank on June 13, 2005
  10. statistics

    Suppose a random sample of size 50 is selected from a population with σ = 10. Find the value of the standard error of the mean in each of the following cases (use the finite population correction factor if appropriate). a. The population size is infinite

    asked by Vanessa on April 15, 2014
  11. Statistics

    The level of nitrogen oxides (NOX) in the exhaust of a particular car model varies with mean 0.9 grams per mile and standard deviation 0.15 grams per mile . (a) What sample size is needed so that the standard deviation of the sampling distribution is 0.01

    asked by Terra on January 12, 2012
  12. statistics

    72% working women use computers choose 5 at random whats the probility at least 1 does not use a computer whats the probility that all 5 use a computer

    asked by max on September 17, 2011
  13. Statistics

    Accrotime is a manufacturer of quartz crystal watches. Accrotime researchers have shown that the watches have an average life of 32 months before certain electronic components deteriorate, causing the watch to become unreliable. The standard deviation of

    asked by Amy on November 16, 2016
  14. statistics

    A simple random sample of 40 items resulted in a sample mean of 25. The population standard deviation is 5. a. What is the standard error of the mean (to 2 decimals)? b. At 95% confidence, what is the margin of error (to 2 decimals)?

    asked by Vanessa on April 21, 2014
  15. Statistics

    Wendy's restaurant has been recognized for having the fastest average service time among fast food restaurants. In a benchmark study, Wendy's average service time of 2.2 minutes was less than those of Burger King, Chick-fil-A, Krystal, McDonald's, Taco

    asked by Kelly Luth on February 20, 2017
  16. statistics

    A survey for brand recognition is done and it is determined that 68% of consumers have heard of Dull Computer Company. If a survey of 800 randomly selected consumers is to be held would it be unusual for 554 of them to recognize Dull Computer Company?

    asked by Amy on October 30, 2013
  17. Statistics

    The weights of the fish in a certain lake are normally distributed with a mean of 15lbs. and standard deviation of 6lbs. If a sample of 5 fish are taken from the lake, find the probability their means weights are between 12.6 lbs. and 18.6 lbs.

    asked by Amy on October 30, 2013
  18. Statistics

    A manufacturer ship toasters in cartons of 10. In each carton, they estimate a 20% chance that one of the toasters will need to be sent back for minor repairs. What is the probability, that in one carton there will be 5 toasters that need repair? I have no

    asked by Nick on October 5, 2013
  19. Statistics

    you roll two fair dice, a green one and a red one? (a) are the outcomes on the dice independent? (b)Find P(1 on green die and 2 on red die) (c)Find P(2 on green die and 1 on red die) (d)Find P(1 on green die and 2 on red die) or (2 on green die and 1 on

    asked by John on October 30, 2016
  20. Statistics

    If the probability of a newborn child being female is 0.5, find the probability that in 100 births, 55 or more will be female. Use the normal distribution to approximate the binomial distribution.

    asked by Kayla on February 10, 2013
  21. Statistics

    Automobile repair costs continue to rise with the average cost now at $367 per repair (U.S. News & World Report website, January 5, 2015). Assume that the cost for an automobile repair is normally distributed with a standard deviation of $88. Answer the

    asked by Anonymous on October 29, 2018
  22. Statistics

    A certain organization recommends the use of passwords with the following​ format: consonant comma consonant, consonant comma vowel comma consonant comma vowel comma consonant comma number comma number consonant, vowel, consonant, vowel, consonant,

    asked by Naomi on June 21, 2018
  23. statistics

    the probability that a house in an urban area will develop a leak is 5%. if 23 houses are randomly selected, what is the probability that none of the houses will develop a leak?

    asked by sara on April 28, 2013
  24. statistics

    An IRS auditor randomly selects 3 tax returns from 58 returns of which 8 contain errors. What is the probability that she selects none of those containing errors?

    asked by Kerri on September 19, 2010
  25. statistics

    The probability that a house is burglarized in the city is 5%. If 50 houses are randomly selected, what is the probability that none will be burglarized?

    asked by Sherry on July 14, 2012
  26. Statistics

    A sign on the gas pump of a certain chain of gasoline stations encourages customers to have their oil checked, claiming that one out of every four cars should have its oil topped up. What is the probability that exactly 3 of the next 10 cars entering a

    asked by Matt on February 10, 2007
  27. statistics

    A survey found that 25% of pet owners had their pets bathed professionally rather than do it themselves. If 18 pet owners are randomly selected, find the probability that exactly 5 people have their pets bathed professionally.

    asked by Anonymous on October 5, 2010
  28. Statistics

    The control group's score of 47.26 on the pretest put it at the 26th percentile. Does this percentile score represent nominal, ordinal, or interval scale data?

    asked by Annaa on February 16, 2019
  29. Statistics

    A physical therapist wants to determine the difference in the proportion of men and women who participate in regular sustained physical activity. What sample size should be obtained if he wishes the estimate to be within four percentage points with 99 ​%

    asked by Zechariah on July 6, 2016
  30. statistics

    A data set includes body temperatures of healthy adult humans for which x= 98.2 and s=0.64 F. Complete parts a) and b) below a) what is the best point estimate of the mean body temperature of all healthy humans? The best point estimate is F. b) Using the

    asked by anonymous on November 19, 2013
  31. statistics

    The Information Systems Audit and Control Association surveyed office workers to learn about the anticipated usage of office computers for personal holiday shopping. Assume that the number of hours a worker spends doing holiday shopping on an office

    asked by Jenna on April 4, 2017
  32. Statistics

    A particular fruit's weights are normally distributed, with a mean of 308 grams and a standard deviation of 31 grams. The heaviest 9% of fruits weigh more than how many grams? Give your answer to the nearest gram.

    asked by Sarah S-Help! on April 12, 2011
  33. Statistics

    The home states of a certain group of people are distributed as follows: 53 percent are from MISSOURI, 21 percent are from KANSAS, and 26 percent are from IOWA. (No one in the group had a home state other than one of these three.) (Note: Your answer to the

    asked by Lucy King on March 20, 2012
  34. Statistics

    Thank you!! A survey of an urban university (population of 25,450) showed that 750 of 1100 students sampled attended a home football game during the season. What inferences can be made about student attendance at football games? Using the 99% level of

    asked by Jenny on December 19, 2007
  35. statistics

    Over the past several months, an adult patient has been treated for tetany (severe muscle spasms). This condition is associated with an average total calcium level below 6 mg/dl. Recently, the patient's total calcium tests gave the following readings (in

    asked by Interval Estimate on April 11, 2015
  36. statistics

    The red face cards and the black cards numbered 2-9 are put into a bag. Four cards are drawn at random without replacement. Find the following probabilities: a) All 4 cards are red b) 2 cards are red and two cards are black c) At least one of the red cards

    asked by oscar on December 12, 2010
  37. statistics

    Jim Tree sells trees. The mean length of the trees purchased was 68 inches with a standard deviation of 10 inches. Jim wants to know what percent of his sales were more than 84 inches tall. He can use the standard normal distribution to help him. He asks,

    asked by Jessie on March 20, 2013
  38. Statistics

    The law of large numbers tells us what happens in the long run. Like many games of chance, the numbers racket has outcomes so variable - one three-digit number wins $600 and all others win nothing - that gamblers never reach "the long run." Even after many

    asked by Ray on February 25, 2014
  39. Statistics

    The lengths of pregnancies are normally distributed with a mean of 273 days and a standard deviation of 20 days. If 64 women are randomly selected, find the probability that they have a mean pregnancy between 273 days and 275 days.

    asked by Jane on February 10, 2013
  40. statistics

    In a carnival game, a player spins a wheel that stops with the pointer on one (and only one) of three colors. The likelihood of the pointer landing on each color is as follows: 65 percent BLUE, 22 percent RED, and 13 percent GREEN. Note: Your answers

    asked by Sydney on March 31, 2013
  41. statistics

    Ina study designed to test the effectiveness magnets for treating back pain, 35 patients were given a treatment with magnets and also a sham treatment without magnets. Pain was measured using a scale from 0(no pain) to 100(extreme pain) after the given

    asked by anonymous on November 18, 2013
  42. Statistics

    Suppose that 30% of all college students smoke cigarettes. A sample of 18 is selected randomly. What is the probability that exactly 10 students smoke? Round your answer to four decimal places.

    asked by Anonymous on November 6, 2016
  43. statistics

    Go to a local library; collect a sample of books consisting of the ages of book (based on copyright dates). Plan and describe the sampling procedure, then use the results to construct a confidence interval estimate of the mean age of all books in the

    asked by jen on June 26, 2015
  44. statistics

    The Economic Policy Institute periodically issues reports on wages of entry level workers. The Institute reported that entry level wages for male college graduates were $21.68 per hour and for female college graduates were $18.80 per hour in 2011 (Economic

    asked by gabby on October 1, 2015
  45. statistics

    A national park is famous for its beautiful desert landscape and its many natural rock formations. The following table is based on information gathered by a park ranger of all rock formations of at least 3 feet. The height of the rock formation is rounded

    asked by Brittany Buford on November 1, 2011
  46. Statistics

    A stationary store has decided to accept a large shipment of ball-point pens if an inspection of 20 randomly selected pens yields no more than two defective pens. a) find the probability that this shipment is accepted if 5% of the total shipment is

    asked by Elayna on August 7, 2013
  47. Statistics

    The yearly rainfall in Vancouver, B.C. follows a normal distribution with standard deviation 172 mm. In 20% of years, the city gets over 1200 mm of rain. What is the mean annual rainfall in Vancouver (in mm)? The answer is 1055.5 mm....not sure how to get

    asked by May on December 14, 2017

    According to Masterfoods, the company that manufactures M&M’s, 12% of peanut M&M’s are brown, 15% are yellow, 12% are red, 23% are blue, 23% are orange and 15% are green. Compute the probability that two randomly selected peanut M&M’s are both blue.

    asked by MIA on July 24, 2013
  49. Statistics

    One event A is _________________ of another event B if the probabilty of event A has occurred given event B is the same as the probability that A will occur with no knowledge of B. disjoint mutually exclusive dependent independent

    asked by John on November 15, 2012
  50. Statistics

    The body temperatures of adults are normally distributed with a mean of 98.6 degree F and a standard deviation of 0.60 degree F. If 36 adults are randomly selected, find the probability that their mean body temperature is greater than 98.4 degree F.

    asked by Maile on February 10, 2013
  51. statistics

    {Exercise 3.55} Morningstar tracks the total return for a large number of mutual funds. The following table shows the total return and the number of funds for four categories of mutual funds (Morningstar Funds500, 2008). a. Using the number of funds as

    asked by abdull on October 16, 2011
  52. statistics

    A researcher at a major hospital wishes to estimate the proportion of the adult population of the U.S. that has high blood pressure. How large a sample is needed in order to be 99% confident that the sample proportion will not differ from the tgrue

    asked by chalulu on March 13, 2011
  53. Statistics

    The Jones family was one of the first to come to the U.S. They had 9 children. Assuming that the probability of a child being a girl is .5, find the probability that the Jones family had at least 5 girls.

    asked by Kevin on October 1, 2017
  54. statistics

    The amount of corn chips dispensed into a 16-ounce bag by the dispensing machine has been identified at possessing a normal distribution with a mean of 16.5 ounces and a standard deviation of 0.1 ounce. Suppose 400 bags of chips were randomly selected from

    asked by UG on November 8, 2011
  55. statistics

    A history class has 75 members. If there is a 12% absentee rate per class meeting, find the mean, variance, and atandard deviation of the number of students who will be absent from each class

    asked by Michelle on May 16, 2011
  56. statistics

    a student takes a true false test that has 13 questions and guesses randomly at each answer. Let X be the number of questions answered correctly. Find P(fewer than 4)

    asked by debbie on June 22, 2016
  57. statistics

    the life of light bulbs is distributed normally. The variance of the life time is 225 and the mean lifetime of a bulb is 590 hours. Find the probability of a bulb lasting for at most 603 hours. Yeah, WTF??? Why me!??!

    asked by Logan on May 3, 2012
  58. statistics

    Most Americans, 67% in fact, say frequent handwashing is the best way to fend off the flu. Despite that, when using public restrooms, women wash their hands only 66% of the time and men wash only 43% of the time. Of the adults using the public restroom at

    asked by Hannah on September 20, 2013
  59. Statistics

    The closing price of Schnur Sporting Goods, Inc., common stock is uniformly distributed between $17 and 35 per share. What is the probability that the stock price will be: More than $31? Less than or equal to $23?

    asked by Barbara on November 21, 2010
  60. Statistics

    The Boeing 757-200 ER airliner carries 200 passengers and has doors with a height of 72 inches. Heights of men are normally distributed with a mean of 69 inches and a standard deviation of 2.8 inches. b) assume that half of the 200 passengers are men, what

    asked by Liz on April 8, 2013
  61. statistics

    for a standard normal curve, find the z-score that separates the bottom 30% from the top 70%

    asked by kay on November 5, 2008
  62. Statistics

    According to insurance records a car with a certain protection system will be recovered 89% of the time. Find the probability that 3 of 7 stolen cars will be recovered.

    asked by sc on May 3, 2012
  63. statistics

    A researcher wishes to estimate the proportion of college students who cheat on exams. A poll of 490 college students showed that 33% of them had, or intended to, cheat on examinations. Find the margin of error for the 95% confidence interval. solution I

    asked by Lucky Lady on June 19, 2014
  64. statistics

    the probability that a football game will go into overtime is 17%. In 240 randomly selected football games, what is the mean and the standard deviation of the number that went into overtime

    asked by erin on June 23, 2013
  65. Statistics

    If the alpha level is changed from a=.05 to a=.01. a. What happens to the boundaries for the critical region? b. What happens to the probability of a Type I error?

    asked by Lyn on December 20, 2013
  66. Statistics

    a manufacturing machine has a 8% defect rate. if 5 items are chosen at random, what is the probability that at least one will have a defect

    asked by Mae on June 11, 2017
  67. Statistics

    A major department store chain is interested in estimating the average amount its credit card customers spent on their first visit to the chain's new store in the mall. Fifteen credit card accounts were randomly sampled and analyzed with the following

    asked by Melanie on November 14, 2012
  68. statistics

    The amount of snow fall falling in a certian mountain range is normally distributed with a mean of 83 inches, and a standard deviation of 16 inches. What is the probability that the mean annual snowfall during 64 randomly picked years will exceed 85.8

    asked by kasey on March 4, 2009
  69. Statistics

    An American roulette wheel has 38 slots, of which 18 are black, 18 are red, and 2 are green. When the wheel is spun, the ball is equally likely to come to rest in any of the slots. Gamblers bet on the roulette by placing chips on a table that lays out the

    asked by Anonymous on April 19, 2018
  70. Statistics

    Find the probability of getting a prime number thrice by tossing a die 10 times.

    asked by Barney on May 7, 2017
  71. Statistics

    A CBS News/New York Times survey found that 97% of Americans believe that texting while driving should be outlawed (CBS News website, January 5, 2015). a. For a sample of 10 Americans, what is the probability that at least 8 say that they believe texting

    asked by Jack Rogers on February 20, 2017
  72. statistics

    Fast Auto Service provides oil and lube service for cars. It is known that the mean time taken for oil and lube service at this garage is 15 minutes per car and the standard deviation is 2.4 minutes. The management wants to promote the business by

    asked by Karinna on February 14, 2009
  73. statistics

    The average electric bill in a residential area is $72 for the month of May. The standard deviation is $6. If the amounts of electric bills are normally distributed, find the probability that the mean of the bill for 15 residents will be less thatn $75

    asked by Bunny on May 5, 2012
  74. Statistics

    Suppose a basketball player is an excellent free throw shooter and makes 90% of his free throws (i.e., he has a 90% chance of making a single free throw). Assume that free throw shots are independent of one another. Suppose this player gets to shoot three

    asked by Grace on March 17, 2013
  75. Statistics

    An automatic machine in a manufacturing process is operating properly if the lengths of an important subcomponent are independently and normally distributed with a mean of 120 cm and a standard deviation of 4.7 cm. Find the probability that if 3 are

    asked by Meghan on September 21, 2011
  76. statistics

    You are ordering a new home theater system that consists of a TV, surround sound system, and DVD player. You can choose from 1616 different TVs, 2222 types of surround sound systems, and 1919 types of DVD players. How many different home theater systems

    asked by Hallie on July 25, 2017
  77. statistics

    The number of hours per week that the television is turned on is determined for each family in a sample. The mean of the data is 30 hours and the median is 26.2 hours. Twenty-four of the families in the sample turned on the television for 15 hours or less

    asked by Anonymous on October 3, 2015
  78. Statistics

    A national caterer determined that 87% of the people who sampled their food said that it was delicious. A random sample of 144 people is obtained from a population of 5000. The 144 people are asked to sample the caterer's food. If sample proportion, P^, is

    asked by Grace on March 22, 2013
  79. Statistics

    Suppose a certain species bird has an average weight of xbar 3.40 grams. Based on previous studies, we can assume that the weights of these birds have a normal distribution with sigma 0.29 grams. Find the sample size necessary for a 98% confidence level

    asked by John on July 16, 2010
  80. Statistics

    It is reported that 72% of working women use computers at work. Choose 5 working women at random. Find a. The probability that at least 1 doesn't use a computer at work b. The probability that all 5 use a computer in their jobs

    asked by Amber on November 11, 2014
  81. Statistics

    Hello. I would like to ask a college statistics question. Q. One hundred draws are made at random with replacement from the box [1,2,2,5]. The draws come out as follows:17 [1]'s, 54 [2]'s, 29 [5]'s. Fill in the blanks, using the options below; show work.

    asked by Daniel on March 28, 2013
  82. statistics

    Suppose a brewery has a filling machine that fills 12 ounce bottles of beer. It is known that the amount of beer poured by this filling machine follows a normal distribution with a mean of 12.44 ounces and a standard deviation of 0.06 ounce. Find the

    asked by Anonymous on November 6, 2011
  83. statistics

    The customer bills in a family restaurant are normally distributed. The bills mean is $28 and has a standard deviation of $6. a. Identify what the random variable you are measuring is in this problem. b. What is the probability that a randomly selected

    asked by James on June 22, 2013
  84. Statistics

    A particular fruit's weights are normally distributed, with a mean of 353 grams and a standard deviation of 6 grams. If you pick one fruit at random, what is the probability that it will weigh between 334 grams and 344 grams?

    asked by Daniel on May 4, 2015
  85. Statistics

    A coffee company wants to make sure that there coffee is being served at the right temperature. If it is too hot, the customers could burn themselves. If it is too cold, the customers will be unsatisfied. The company has determined that they want the

    asked by Rachel on March 15, 2012
  86. statistics

    A salesman who is on the road visiting clients thinks that on average he drives the same distance each day of the week. He keeps track of his mileage for several weeks and discovers that he averages 122 miles on Mondays, 203 miles on Tuesdays, 176 miles on

    asked by Bettie on April 6, 2013
  87. statistics

    Richard has been given a 5-question multiple-choice quiz in his history class. Each question has three answers, of which only one is correct. Since Richard has not attended the class recently, he doesn't know any of the answers. The success occurs if

    asked by Anonymous on November 9, 2010

    A statistics professor conducted a study on the effect of playing video games on a student’s test scores. On the first day of class, she randomly divided her classes into groups. Group one played video games 2 hours a day, group two played video games 4

    asked by DEBBIE on February 5, 2011
  89. statistics

    Assume a binomial probability distribution has p = .60 and n = 200. c. What is the probability of 100 to 110 successes (to 4 decimals)? d. What is the probability of 130 or more successes (to 4 decimals)?

    asked by Vanessa on April 6, 2014
  90. statistics

    Lorraine was in a hurry when she computed a confidence interval for μ. Because σ was not known, she used a Student's t distribution. However, she accidentally used degrees of freedom n instead of n - 1. Will her confidence interval be longer or shorter

    asked by jr on February 18, 2012
  91. statistics

    in a test for esp a subject is told that cards the experimenter can see but he cannot contain either a star, a circle, a wave, or a square. as the experimenter looks at each of 20 cards in turn, the subject names the shape on the card. a subject who is

    asked by steven on March 24, 2010
  92. statistics

    According to a recent survey, 38% of americans get 6 hours or less of sleep each night. If 25 people are selected, find the probability that 14 or more people will get 6 hours or less sleep each night..

    asked by brin on February 3, 2010
  93. Statistics

    Sulfur compounds cause "off-odors" in wine, so winemaker want to know the odor threshold, the lowest concentration of a compound that the human nose can detect. The odor threshold for dimethyl sulfide (DMS) in trained wine tasters is about 25 micrograms

    asked by Ryan on May 6, 2012
  94. Statistics

    A recent study stated that if a person chewed gum the average number of sticks of gum he or she chewed daily was eight. To teat the claim a researcher selected a random sample of 36 gum chewers and found the mean number of sticks of gum chewed per day was

    asked by Camille on April 8, 2009
  95. statistics

    In a study designed to test the effectiveness of magnets for treating back pain, 40 patients were given a treatment with magnets and also a sham treatment without magnets. Pain was measured using a scale from 0 to 100. After given the magnet treatments,

    asked by Sharie on November 19, 2013
  96. statistics

    A researcher reports an F-ratio with df = 2, 36 from an independent-measures research study. Based on the df values, how many treatments were compared in the study and what was the total number of subjects participating in the study? a. 2 treatments and 37

    asked by Robbie on November 14, 2012
  97. Statistics

    A marketing research firm wishes to determine if the residents of Caldwell, Idaho, would be interested in a new downtown restaurant. The firm selects a simple random sample of 120 phone numbers from the Caldwell phone book and calls each household. Only 62

    asked by Kevin on November 9, 2015
  98. Statistics

    Coaching companies claim that their courses can raise the SAT scores of high school students. But students who retake the SAT without paying for coaching also usually raise their scores. A random sample of students who took the SAT twice found 427 who were

    asked by Anonymous on May 22, 2014
  99. Statistics

    I really need help with this problem. I am not sure what the question is asking and how to approach it! Thanks in advance! Its known that 2/3 of humans have a dominant right foot or eye. Is there also a right-sided dominance in kissing behaviour? In a

    asked by Hanna on March 31, 2009
  100. Statistics

    The Tribune claims that the time of travel from downtown to the University via the bus has an average of µ = 27 minutes. A student who normally takes this bus believes that µ is greater than 27 minutes. A sample of six ride times taken to test the

    asked by Stanley on January 25, 2013