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

    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
  3. 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
  4. 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
  5. 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
  6. 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
  7. 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
  8. 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
  9. 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
  10. 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
  11. 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
  12. 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
  13. 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
  14. 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
  15. 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
  16. 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
  17. 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
  18. 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
  19. 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
  20. 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

    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
  22. 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
  23. 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
  24. 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
  25. 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
  26. 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
  27. 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
  28. 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
  29. 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
  30. 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
  31. 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
  32. 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
  33. 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
  34. 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
  35. 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
  36. 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
  37. 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

    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
  39. 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
  40. 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
  41. Statistics

    A total of 16 mice are sent down a maze, one by one. From previous experience, it is believed that the probability a mouse turns right is .38 a) What is the probability that exactly 8 of these 16 mice turn right? b) What is the probability that 8 or fewer

    asked by please help on October 12, 2012
  42. 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
  43. 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
  44. 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
  45. Statistics

    The percentage of adults who have been told at some point that they have hyptertension is 23.53%. If 10 adults are randomly selected, what is the probability that at least 8 have been told that they have hypertension?

    asked by Raj on October 9, 2008
  46. 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
  47. 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
  48. Statistics

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

    asked by Barney on May 7, 2017
  49. 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
  50. 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
  51. 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
  52. Statistics

    If the correlation coefficient is 0.790, what is the explained variation? A. 37.6% B. 62.4% C. 79% D. 21%

    asked by Ashleigh on December 11, 2011
  53. Statistics

    An electrical firm which manufactures a certain type of bulb wants to estimate its mean life. Assuming that the life of the light bulb is normally distributed and that the standard deviation is known to be 40 hours, how many bulbs should be tested so that

    asked by Blerp on November 16, 2012
  54. 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
  55. 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
  56. 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
  57. 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
  58. 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
  59. 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
  60. 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
  61. Statistics

    Listed below are body temperatures for four subjects measured at two different times in a day. Body Temperature (°𝐹) 𝑎𝑡 6 𝑎𝑚: 98.0,97.0,98.6,97.4 Body Temperature (°𝐹) 𝑎𝑡 6 𝑝𝑚: 98.0,97.6,98.8,98.0 Assume the sample data are

    asked by Nick on April 26, 2016
  62. Statistics

    From a sample with n equals=24​, the mean number of televisions per household is 3 with a standard deviation of 1 television. Using​ Chebychev's Theorem, determine at least how many of the households have between 1 and 5 televisions.

    asked by Addison on September 18, 2016
  63. 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
  64. 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
  65. 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
  66. 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
  67. 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
  68. 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
  69. 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
  70. statistics

    It is thought that prehistoric Indians did not take their best tools, pottery, and household items when they visited higher elevations for their summer camps. It is hypothesized that archaeological sites tend to lose their cultural identity and specific

    asked by sharon on August 22, 2010
  71. statistics

    a study of the time spent shopping in a supermarket for a market basket of 20 specific items showed an approximately uniform distribution between 20 minutes and 40 minutes. What is the probability that the shopping time will be a) between 25 and 30

    asked by ann on January 6, 2011
  72. 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
  73. Statistics

    1. A study of 40 people found that they could do on the average15 pull ups with a standard deviation of .6. Find the 99% confidence interval for the mean of the population. 2. A study of 50 pizza delivery workers found that they could make 6 deliveries per

    asked by Anonymous on May 9, 2013
  74. 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
  75. 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
  76. 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

    the percentage of adults who have at some point in their life been told that they have hypertension is 23.53%. If 8 adults are randomly selected, find the probability that between 2 and 4 of then inclusive have been told that they have hypertension

    asked by amber on January 26, 2012
  78. statistics

    If the standard deviation for waiting times in a line is 5 minutes, the standard deviation for the averages of 30 randomly chosen waiting times is _____ minutes.

    asked by Sarah on November 6, 2011
  79. Statistics

    A survey of 250 lobster fisherman found that they catch an average of 32 pounds of lobster per day with a standard deviation of four pounds. If a random sample of 30 lobster fisherman is selected, what is the probability that their average catch is less

    asked by Mark on May 7, 2014
  80. statistics

    The average height of 18-year-old American women is 64.2 inches. You wonder whether the mean height of this year’s female graduates from your local high school is different from the national average. You measure an SRS of 78 female graduates and find

    asked by nina on April 11, 2013
  81. 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
  82. statistics

    Five percent of all items sold by mail order company are returned by customers for a refund. Find the probability that, of two items sold during a given hour by this company, a) both will be returned for a refund b) neither will be returned for a refund

    asked by Mikey on October 19, 2011
  83. statistics

    The 92 million Americans of age 50 and over control 50% of all discretionary income (AARP Bulletin, March 2008). AARP estimated that the average annual expenditure on restaurants and carry out food was $1873 for individuals in this age group. Suppose this

    asked by Anonymous on July 20, 2011
  84. statistics

    John Davis, a manager of a supermarket, wants to estimate the proportion of customers that will be using food stamps at his store. How large a sample is required to estimate the true proportion to within 3% with 98% confidence?

    asked by Mark on May 4, 2014
  85. statistics

    This table shows claims and their probablity for an insurance company. AMOUNT OF CLAIM PROBABILITY $0 0.65 $50,000 0.25 $100,000 0.06 $150,000 0.02 $200,000 0.01 $250,000 0.01 1. Calculate the expected value? 2. How much should the company charge as an

    asked by Anonymous on November 28, 2011
  86. statistics

    the mean annual salary for employees at a company is 36,000. at the end of the year, each employee receives a 1,000 bonus and a 5% raise( based on salary)what is the new annula sala

    asked by angela on April 9, 2013
  87. Statistics

    The probability that a university graduate will be offered no jobs within a month of graduation is estimated to be 5%. The probability of receiving one, two, and three job offers has similarly been estimated to be 37%, 27%, and 31%. Determine the following

    asked by Miranda on May 19, 2010
  88. Statistics

    If we know that the length of time it takes a college student to find a parking spot in the library parking lot follows a normal distribution with a mean of 3.5 minutes and a standard deviation of 1 minute, find the point in the distribution in which 75.8%

    asked by Pacifico on March 19, 2010
  89. statistics

    Suppose that fÈ and fX|È are described by simple closed-form formulas. Suppose that È is one-dimensional but X is high-dimensional. a) Suppose that a specific value x of the random variable X has been observed. Is it true that the calculation of the LMS

    asked by alec on April 14, 2015
  90. 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
  91. statistics

    A researcher used an analysis of variance to compare three treatment conditions with a separate sample of n = 8 participants in each treatment. The results of the analysis are shown in the following summary. Fill in all missing values in the table. (Hint:

    asked by Robbie on November 15, 2012
  92. 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
  93. statistics

    At Guadalajara Airport, passengers must claim their luggage and then proceed to Customs. In the Customs area, each passenger will press a button that activates a modified stoplight. This light has only red and green bulbs. If the green light shows, the

    asked by Stephanie on January 25, 2010
  94. Statistics

    Retired workers and disabled workers both receive Social Security benefits. What information would we need to test the claim that the difference in monthly benefits between the two groups is greater than $30 at the 0.05 level of significance? Write out the

    asked by Marilyn on June 7, 2018
  95. statistics

    A mail order company has 8% success rate. If it mails advertisements to 600 people, find the probability of getting less than 40 sales.

    asked by Anonymous on April 9, 2013
  96. Statistics

    A stationary store has decided to accept a large shipment of ball-point pens if an inspection of 18 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 Warren on September 28, 2018
  97. Statistics

    Sickle cell anemia is a genetic blood disorder where red blood cells lose their flexibility and assume an abnormal, rigid, "sickle" shape, which results in a risk of various complications. If both parents are carriers of the disease, then a child has a

    asked by Neveah on February 5, 2016
  98. Statistics

    In 1998 a San Diego Reproductive clinic reported 49 live births to 207 women under the age of 40 who had previously been unable to get pregnant. Using the 90% confidence interval calculated above, would it be misleading for the clinic to report a success

    asked by Jeffrey on October 27, 2013
  99. Statistics

    A survey is being planned to determine the mean amount of time corporation executives watch television. A pilot survey indicated that the mean time per week is 12 hours, with a standard deviation of 3 hours. It is desired to estimate the mean viewing time

    asked by Shyra on December 2, 2010
  100. 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