Question: From the display below pick five cards (

> To protect baby scallops and ensure the survival of the species, the U.S. Fisheries and Wildlife Service requires that an average scallop must weigh at least 1/36 pound. The harbormaster at a Massachusetts port randomly selected 18 bags of scallops from

> Find the associated z-score for each of the following standard normal areas. a. Lowest 6 percent b. Highest 40 percent c. Lowest 7 percent

> After 7 months, none of 238 angioplasty patients who received a drug-coated stent to keep their arteries open had experienced restenosis (re-blocking of the arteries). (a) Use MINITAB to construct a 95 percent binomial confidence interval for the proport

> An experimental medication is administered to 16 people who suffer from migraines. After an hour, 10 say they feel better. Is the medication effective (i.e., is the percent who feel better greater than 50 percent)? Use α = .10, explain fully, and show al

> A quality standard says that no more than 2 percent of the eggs sold in a store may be cracked (not broken, just cracked). In 3 cartons (12 eggs each carton), 2 eggs are cracked. (a) At the .10 level of significance, does this prove that the standard is

> An automaker states that its cars equipped with electronic fuel injection and computerized engine controls will start on the first try (hot or cold) 99 percent of the time. A survey of 100 new car owners revealed that 3 had not started on the first try d

> The historical on-time percentage for Amtrak’s Sunset Limited is 10 percent. In July, the train was on time 0 times in 31 runs. At the .10 level of significance, has the on-time percentage fallen? Explain clearly. Hint: Use Excel to calculate the cumulat

> On a police sergeant’s examination, the historical mean score was 80 with a standard deviation of 20. Four officers who were alleged to be cronies of the police chief scored 195, 171, 191, and 189, respectively, on the test. This led to allegations of ir

> A recent article states that there is a 2 percent chance that an asteroid 100 meters or more in diameter will strike the earth before 2100. Which type of probability (classical, empirical, subjective) do you think this is?

> The U.S. Cesarean section delivery rate in a recent year was estimated at 20.6 percent. Which type of probability (classical, empirical, subjective) do you think this is?

> In the first year after its release, 83 percent of emergency room doctors were estimated to have tried Dermabond glue (an alternative to sutures in some situations). Which type of probability (classical, empirical, subjective) do you think this is?

> Bob says he is 50 percent sure he could swim across the Thames River. Which type of probability (classical, empirical, subjective) do you think this is?

> Find the associated z-score for each of the following standard normal areas. a. Highest 10 percent b. Lowest 50 percent c. Highest 7 percent

> A survey showed that 44 percent of online Internet shoppers experience some kind of technical failure at checkout (e.g., when submitting a credit card) after loading their shopping cart. Which type of probability (classical, empirical, subjective) do you

> A judge concludes that there is a 20 percent chance that a certain defendant will fail to appear in court if he is released after paying a full cash bail deposit. Which type of probability (classical, empirical, subjective) do you think this is?

> For male high school athletes, a news article reported that the probability of receiving a college scholarship is .0139 for basketball players, .0324 for swimmers/divers, and .0489 for lacrosse players. Which type of probabilities (classical, empirical,

> If there are two riders on a city bus, what is the probability that no two have the same birthday? What if there are 10 riders? 20 riders? 50 riders? Hint: Use Learning Stats from McGraw-Hill’s Connect.

> Fifty-six percent of American adults eat at a table-service restaurant at least once a week. Suppose that four American adults are asked if they ate at table-service restaurants last week. What is the probability that all of them say yes?

> In child-custody cases, about 70 percent of the fathers win the case if they contest it. In the next three custody cases, what is the probability that all three win? What assumption(s) are you making?

> A turboprop aircraft has two attitude gyros, driven from independent electrical sources. On a six-hour flight, assume the probability of failure of each attitude gyroscope is 0.0008. Does this achieve “five-nines” reliability (i.e., a probability of at l

> A couple has two children. What is the probability that both are boys, given that the first is a boy?

> There is a 30 percent chance that a bidding firm will get contract A and a 40 percent chance they will get contract B. There is a 5 percent chance that they will get both. Are the events independent?

> Two cards are drawn from an ordinary deck of 52 cards. Find the probability of each event, showing your reasoning carefully. a. Two aces. b. Two red cards. c. Two red aces. d. Two honor cards (A, K, Q, J, 10).

> Joan’s finishing time for the Bolder Boulder 10K race was 1.75 standard deviations faster than the women’s average for her age group. There were 405 women who ran in her age group. Assuming a normal distribution, how many women ran faster than Joan?

> An MBA program offers seven concentrations: accounting (A), finance (F), human resources (H), information systems (I ), international business (B), marketing (M), and operations management (O). Students in the capstone business policy class are assigned

> (a) In a certain state, license plates consist of three letters (A–Z) followed by three digits (0–9). How many different plates can be issued? (b) If the state allows any six-character mix (in any order) of 26 letters and 10 digits, how many unique plate

> A certain model of remote-control Stanley garage door opener has nine binary (off/on) switches. The homeowner can set any code sequence. (a) How many separate codes can be programmed? (b) If you try to use your door opener on 1,000 other garages, how man

> Prior to the start of the 2011 NCAA Men’s Basketball playoffs, the reported odds that Butler University would not make it to the final game were 200 to 1. What was the implied probability that Butler would make it to the finals in 2011?

> The probability of being struck by lightning is .00016. Find the odds against being struck by lightning. Round your answer to the nearest whole number. (www.lightningsafety.noaa.gov)

> The probability that a 2011 Audi A8 is stolen is .0048. Find the odds against the theft of a 2011 Audi A8. Round your answer to the nearest whole number. (www.nhtsa.gov/theft)

> A study showed that trained police officers can detect a lie 65 percent of the time, based on controlled studies of videotapes with real-life lies and truths. What are the odds in favor of a lie being detected?

> To run its network, the Ramjac Corporation wants to install a system with dual independent servers. Employee Bob grumbled, “But that will double the chance of system failure.” Is Bob right? Explain your reasoning with an example.

> Bob owns two stocks. There is an 80 percent probability that stock A will rise in price, while there is a 60 percent chance that stock B will rise in price. There is a 40 percent chance that both stocks will rise in price. Are the stock prices independen

> On Los Angeles freeways during the rush hour, there is an 18 percent probability that a driver is using a hand-held cell phone. Which type of probability (classical, empirical, subjective) do you think this is?

> Bob’s exam score was 2.17 standard deviations above the mean. The exam was taken by 200 students. Assuming a normal distribution, how many scores were higher than Bob’s?

> If Punxsutawney Phil sees his shadow on February 2, then legend says that winter will last 6 more weeks. In 118 years, Phil has seen his shadow 104 times. (a) What is the probability that Phil will see his shadow on a randomly chosen Groundhog Day?

> Bob, Mary, and Jen go to dinner. Each orders a different meal. The waiter forgets who ordered which meal, so he randomly places the meals before the three diners. Let C be the event that a diner gets the correct meal and let N be the event that a diner g

> High levels of cockpit noise in an aircraft can damage the hearing of pilots who are exposed to this hazard for many hours. Cockpit noise in a jet aircraft is mostly due to airflow at hundreds of miles per hour. This 3 × 3 contingency table

> Analysis of forecasters’ interest rate predictions over the period 1982–1990 was intended to see whether the predictions corresponded to what actually happened. The 2 × 2 contingency table below shows the

> Refer to the contingency table shown below. (a) Calculate each probability (i–vi) and explain in words what it means. (b) Do you see evidence that smoking and race are not independent? Explain. (c) Do the smoking rates shown here corres

> Four students divided the task of surveying the types of vehicles in parking lots of four different shopping malls. Each student examined 100 cars in each of four large suburban malls, resulting in the 5 3 4 contingency table shown below. (a) Calculate e

> The probability is 1 in 4,000,000 that a single auto trip in the United States will result in a fatality. Over a lifetime, an average U.S. driver takes 50,000 trips. (a) What is the probability of a fatal accident over a lifetime? Explain your reasoning

> A web server hosting company advertises 99.999 percent guaranteed network uptime. (a) How many independent network servers would be needed if each has 99 percent reliability? (b) If each has 90 percent reliability?

> Which are likely to be independent events? For those you think are not, suggest reasons why. a. Gender of two babies born consecutively in a hospital. b. Car accident rates and the driver’s gender. c. Phone call arrival rates at a university admissions

> A certain airplane has two independent alternators to provide electrical power. The probability that a given alternator will fail on a one-hour flight is .02. What is the probability that (a) both will fail? (b) Neither will fail? (c) One or the other wi

> Find the standard normal area for each of the following. Sketch the normal curve and shade in the area represented below. a. P(Z < -1.28) b. P(Z > 1.28) c. P(-1.96 < Z < 1.96) d. P(-1.65 < Z < 1.65)

> A poker hand (5 cards) is drawn from an ordinary deck of 52 cards. Find the probability of each event, showing your reasoning carefully. a. The first four cards are the four aces. b. Any four cards are the four aces.

> A certain brand of flat white interior latex paint claims one-coat coverage of 400 square feet per gallon. The standard deviation is known to be 20. A sample of 16 gallons is tested. (a) At α = .05 in a left-tailed test, find the β risk and power assumin

> A process is normally distributed with standard deviation 12. Samples of size 4 are taken. Suppose that you wish to test the hypothesis that μ 5 500 at α = .05 in a left-tailed test. (a) What is the β risk if the true mean is 495? If the true mean is 490

> A nuclear power plant replaces its ID card facility access system cards with a biometric security system that scans the iris pattern of the employee and compares it with a data bank. Users are classified as authorized or unauthorized. (a) State the null

> High blood pressure, if untreated, can lead to increased risk of stroke and heart attack. A common definition of hypertension is diastolic blood pressure of 90 or more. (a) State the null and alternative hypotheses for a physician who checks your blood p

> In a commercially available fingerprint scanner (e.g., for your home or office PC), false acceptances are 1 in 25 million, with false rejection rates of 3 percent. (a) Define Type I and II errors. (b) Why do you suppose the false rejection rate is so hig

> Pap smears are a test for abnormal cancerous and precancerous cells taken from the cervix. (a) State a pair of hypotheses and then explain the meaning of a false negative and a false positive. (b) Why is the null hypothesis “null”? (c) Who bears the cost

> If the true mean is 50 and we reject the hypothesis that μ = 50, what is the probability of Type II error?

> Telemarketers use a predictive dialing system to decide whether a person actually answers a call (as opposed to an answering machine). If so, the call is routed to a telemarketer. If no telemarketer is free, the software must automatically hang up the ph

> Find the standard normal area for each of the following. Sketch the normal curve and shade in the area represented below. a. P(Z < -1.96) b. P(Z > 1.96) c. P(Z < 1.65) d. P(Z > -1.65)

> A test-preparation company advertises that its training program raises SAT scores by an average of at least 30 points. A random sample of test-takers who had completed the training showed a mean increase smaller than 30 points. (a) Write the hypotheses f

> Suppose the judge decides to acquit all defendants, regardless of the evidence. (a) What is the probability of Type I error? (b) Why is this a bad policy?

> Suppose you always reject the null hypothesis, regardless of any sample evidence. (a) What is the probability of Type II error? (b) Why is this a bad policy?

> When told that over a 10-year period a mammogram test has a false positive rate of 50 percent, Bob said, “That means that about half the women tested actually have no cancer.” Correct Bob’s mistaken interpretation.

> If we fail to reject the null hypothesis that π = .50 even though the true proportion is .60, what is the probability of Type I error?

> This table shows the distribution of winning times in the Kentucky Derby (a horse race) over 84 years. (a) From the grouped data, calculate the mean. Show your calculations clearly in a worksheet. (b) What additional information would you have gained by

> A random sample of individuals who filed their own income taxes were asked how much time (hours) they spent preparing last year&acirc;&#128;&#153;s federal income tax forms. (a) Estimate the mean. (b) Estimate the standard deviation. (c) Do you think the

> How long does it take to fly from Denver to Atlanta on Delta Airlines? The table below shows 56 observations on flight times (in minutes) for the first week of March 2005. (a) Use the grouped data formula to estimate the mean and standard deviation. (b)

> The self-reported number of hours worked per week by 204 top executives is given below. (a) Estimate the mean, standard deviation, and coefficient of variation using an Excel worksheet to organize your calculations. (b) Do the unequal class sizes hamper

> For patients aged 81 to 90, the probability is .07 that a coronary bypass patient will die soon after the surgery. (a) What is the expected number of operations until the first fatality? (b) What is the probability of conducting 20 or more operations bef

> Find the standard normal area for each of the following, showing your reasoning clearly and indicating which table you used. a. P(-1.22 < Z < 2.15) b. P(-3.00 < Z < 2.00) c. P(Z < 2.00) d. P(Z = 0)

> In the Ardmore Hotel, 20 percent of the customers pay by American Express credit card. (a) Of the next 10 customers, what is the probability that none pay by American Express? (b) At least two? (c) Fewer than three? (d) What is the expected number who pa

> Historically, 5 percent of a mail-order firm’s regular charge-account customers have an incorrect current address in the firm’s computer database. (a) What is the expected number of customer orders until the first one with an incorrect current address pl

> In a certain city, 8 percent of the cars have a burned-out headlight. (a) What is the expected number that must be inspected before the first one with a burned-out headlight is found? (b) What is the probability of finding the first one within the first

> The probability that a bakery customer will order a birthday cake is .04. (a) What is the expected number of customers until the first birthday cake is ordered? (b) What is the probability the first cake order occurs within the first 20 customers?

> The probability of a job offer in a given interview is .25. (a) What is the expected number of interviews until the first job offer? (b) What is the probability the first job offer occurs within the first six interviews?

> At a certain clinic, 2 percent of all pap smears show signs of abnormality. What is the expected number of pap smears that must be inspected before the first abnormal one is found?

> Automobile warranty claims for engine mount failure in a Troppo Malo 2000 SE are rare at a certain dealership, occurring at a mean rate of 0.1 claim per month. (a) What is the probability that the dealership will wait at least 6 months until the next cla

> Systron Donner Inertial manufactures inertial subsystems for automotive, commercial/ industrial, and aerospace and defense applications. The sensors use a one-piece, micromachined inertial sensing element to measure angular rotational velocity or linear

> The HP dvd1040i 20X Multiformat DVD Writer has an MTBF of 70,000 hours. (a) Assuming continuous operation, what is the probability that the DVD writer will last more than 100,000 hours? (b) Less than 50,000 hours? (c) At least 50,000 hours but not more t

> Suppose the average time to service a Noodles & Company customer at a certain restaurant is 3 minutes and the service time follows an exponential distribution. (a) What is the probability that a customer will be serviced in less than 3 minutes? (b) Why i

> (a) Use Excel functions to calculate the mean and standard deviation for weekend occupancy rates (percent) in nine resort hotels during the off-season. (b) What conclusion would a casual observer draw about center and variability, based on your statistic

> Find the standard normal area for each of the following, showing your reasoning clearly and indicating which table you used. a. P(1.22 < Z < 2.15) b. P(-.00 < Z < 3.00) c. P(-2.00 < Z < 2.00) d. P(Z > 0.50)

> M&Ms are blended in a ratio of 13 percent brown, 14 percent yellow, 13 percent red, 24 percent blue, 20 percent orange, and 16 percent green. Suppose you choose a sample of two M&Ms at random from a large bag. (a) Show the sample space. (b) What is the p

> The U.S. Postal Service will ship a Priority Mail&Acirc;&reg; Large Flat Rate Box (120 3 120 3 51&acirc;&#129;&#132;20) anywhere in the United States for a fixed price, regardless of weight. The weights (ounces) of 20 randomly chosen boxes are shown belo

> The durations (minutes) of 26 electric power outages in the community of Sonando Heights over the past five years are shown below. (a) Find the mean, median, and mode. (b) Are the mean and median about the same? (c) Is the mode a good measure of center f

> How many days in advance do travelers purchase their airline tickets? Below are data showing the advance days for a sample of 28 passengers on United Airlines Flight 815 from Chicago to Los Angeles. (a) Calculate the mean, median, mode, and midrange. (b)

> Below are monthly rents paid by 30 students who live off campus. (a) Find the mean, median, and mode. (b) Do the measures of central tendency agree? Explain. (c) Calculate the standard deviation. (d) Sort and standardize the data. (e) Are there outliers

> Chlorine is added to city water to kill bacteria. In a certain year, chlorine content in water from the Lake Huron Water Treatment plant ranged from 0.79 ppm (parts per million) to 0.92 ppm. (a) Use the midrange as a measure of center. (b) Use the Empiri

> Caffeine content in a 5-ounce cup of brewed coffee ranges from 60 to 180 mg, depending on brew time, coffee bean type, and grind. (a) Use the midrange as a measure of center. (b) Use the Empirical Rule to estimate the standard deviation. (c) Why is the a

> Analysis of annualized returns over a 10-year period showed that prepaid tuition plans had a mean return of 6.3 percent with a standard deviation of 2.7 percent, while the Standard & Poor’s 500 stock index had a mean return of 12.9 percent with a standar

> Analysis of portfolio returns over a 20-year period showed the statistics below. (a) Calculate and compare the coefficients of variation. (b) Why would we use a coefficient of variation? Why not just compare the standard deviations? (c) What do the data

> The table below shows average daily sales of Rice Krispies in the month of June in 74 Noodles &amp; Company restaurants. (a) Make a histogram for the data. (b) Would you say the distribution is skewed? (c) Calculate the mean and standard deviation. (d) A

> Find the standard normal area for each of the following, showing your reasoning clearly and indicating which table you used. a. P(0 < Z < 0.50) b. P(-0.50 < Z < 0) c. P(Z > 0) d. P(Z = 0)

> The &acirc;&#128;&#156;expense ratio&acirc;&#128;&#157; is a measure of the cost of managing the portfolio. Investors prefer a low expense ratio, all else equal. Below are expense ratios for 23 randomly chosen stock funds and 21 randomly chosen bond fund

> This year, Dolon Company’s website averaged 12,104 daily views with a standard deviation of 3,026. Last year, the mean number of daily page views was 6,804 with a standard deviation of 1,701. Describe the relative variation in page views in these two yea

> A sample of size n = 70 showed a skewness coefficient of 0.773 and a kurtosis coefficient of 1.277. What is the distribution’s shape?

> A plumbing supplier’s mean monthly demand for vinyl washers is 24,212 with a standard deviation of 6,053. The mean monthly demand for steam boilers is 6.8 with a standard deviation of 1.7. Which demand pattern has more relative variation? Explain.

> At Chipotle Mexican Grill, the number of calories in an order of chips and salsa is normally distributed with a mean of 620 and a standard deviation of 12. Bob’s order had only 580 calories. Was this an outlier? Explain.

> Applicants for a night caretaker position are uniformly distributed in age between 25 and 65. (a) What is the mean age of an applicant? (b) The standard deviation? (c) What is the probability that an applicant will be over 45? (d) Over 55? (e) Between 30

> In a certain year, on average 10 percent of the vehicles tested for emissions failed the test. Suppose that five vehicles are tested. (a) What is the probability that all pass? (b) All but one pass? (c) Sketch the probability distribution and discuss its

> Which of the following could be probability density functions for a continuous random variable? Explain. a. f (x) = .50 for 0 < x < 2 b. f (x) = 2 - x for 0 < x < 2 c. f (x) = .5x for 0 < x < 2

> Which of the following is a continuous random variable? a. Number of Honda Civics sold in a given day at a car dealership. b. Amount of gasoline used for a 200-mile trip in a Honda Civic. c. Distance driven on a particular Thursday by the owner of a Hon

> A sample of 20 pages was taken without replacement from a Yellow Pages directory that has 1,591 pages. (a) Calculate the FPCF for this sample. (b) Should the population be considered effectively infinite?