Q&A Hero

Q: The binomial distribution is frequently used to help companies decide whether to accept or reject a shipment based on the results of a random sample of items from the shipment. For instance, suppose a contract calls for, at most, 10 percent of the items in a shipment to be red. To check this without looking at every item in the large shipment, a sample of n = 10 items is selected. If 1 or fewer are red, the shipment is accepted; otherwise it is rejected. Using probability, determine whether this is a "good" sampling plan. (Assume that a bad shipment is one that has 20 percent reds.)

Q: A company that makes chocolate chip cookies has found that the number of chips per cookie follows a Poisson distribution. What should the minimum average number of chips be to result in at least 98 percent of the cookies having more than 2 chips? Find the minimum average to nearest whole chip (i.e. choose an average that is a whole number).

Q: Explain how to use the binomial distribution table when p, the probability of a success, exceeds 0.50.

Q: A small city has 2 ambulances. Emergency calls for ambulances arrive randomly with an average of 0.2 calls per hour. They are concerned about the possibility of both ambulances being busy when an additional call comes in. What is the probability of more than 2 calls in a 1-hour period? Determine the correct distribution, explain why it is the best distribution to use, and find the probability.

Q: Explain how to determine whether the binomial distribution can be used in a particular application.

Q: Explain what the expected value of a discrete random variable measures.

Q: What is the difference between a discrete random variable and a continuous random variable?

Q: Beacon Hill Trees & Shrubs currently has an inventory of 10 fruit trees, 8 pine trees, and 14 maple trees. It plans to give 4 trees away at next Saturday's lawn and garden show in the city park. The 4 winners can select which type of tree they want. Assume they select randomly. What is the probability that no fruit trees and 2 of each of the others will be selected? A) 0.0058 B) 0.0218 C) 0.0355 D) 0.0709

Q: John Thurgood founded a company that translates Chinese books into English. His company is currently testing a computer-based translation service. Since Chinese symbols are difficult to translate, John assumes the computer program will make some errors, but then so do human translators. The computer error rate is supposed to be an average of 3 per 400 words of translation. Suppose John randomly selects a 1,200-word passage. Assuming that the Poisson distribution applies, if the computer error rate is actually 3 errors per 400 words, find the probability that fewer than 9 errors will be found. A) 0.000123 B) 0.0141 C) 0.0415 D) 0.4557

Q: College-Pro Painting does home interior and exterior painting. The company uses inexperienced painters that do not always do a high-quality job. It believes that its painting process can be described by a Poisson distribution with an average of 4.8 defects per 400 square feet of painting. What is the probability that six randomly sampled sections of size 400 square feet will each have 7 or fewer blemishes? A) 0.2818 B) 0.3414 C) 0.4857 D) 0.6509

Q: A stock portfolio contains 20 stocks. Of these stocks, 10 are considered "large-cap" stocks, 5 are "mid-cap," and 5 are "small cap." The portfolio manager has been asked by his client to develop a report that highlights 7 randomly selected stocks. When she presents her report to the client, all 7 of the stocks are large-cap stocks. The client is very suspicious that the manager has not randomly selected the stocks. She believes that the chances of all 7 of the stocks being large cap must be very low. Compute the probability of all 7 being large cap. A) 0.0015 B) 0.0008 C) 0.0121 D) 0.0309

Q: Following is the Project Evaluation and Review Technique (PERT) network used to execute a marketing campaign at TeaTime Inc. Calculate the variance for the project. a. 2.5 weeks b. 3.0 weeks c. 3.5 weeks d. 4.0 weeks

Q: The Weyerhauser Lumber Company headquartered in Tacoma, Washington, is one of the largest timber and wood product companies in the world. Weyerhauser manufactures plywood at one of its Oregon plants. Plywood contains minor imperfections that can be repaired with small "plugs." One customer will accept plywood with a maximum of 3.5 plugs per sheet on average. Suppose a shipment was sent to this customer and when the customer inspected two sheets at random, 10 plugged defects were counted. What is the probability of observing 10 or more plugged defects if in fact the 3.5 average per sheet is being satisfied? A) 0.1887 B) 0.1695 C) 0.2115 D) 0.2675

Q: In the context of project management, _____ a project involves releasing and reassigning people. a. closing b. organizing c. defining d. planning

Q: A new phone answering system installed by the Ohio Power Company is capable of handling five calls every 10 minutes. Prior to installing the new system, company analysts determined that the incoming calls to the system are Poisson distributed with a mean equal to two every 10 minutes. If this incoming call distribution is what the analysts think it is, what is the probability that in a 10-minute period more calls will arrive than the system can handle?A) 0.174B) 0.0812C) 0.0166D) 0.0233

Q: In the context of the Project Evaluation and Review Technique (PERT), which of the following is true of the beta probability distribution approach? a. It allows managers to identify the best case, worst case, and most likely case for activity times. b. It describes the inherent similarity in the optimistic, most probable, and pessimistic time estimates. c. It is rigid in characterizing the distribution of times. d. It forces activity times to a symmetric normal probability distribution.

Q: A corporation has 11 manufacturing plants. Of these, 7 are domestic and 4 are located outside the United States. Each year a performance evaluation is conducted for 4 randomly selected plants. What is the probability that a performance evaluation will include 2 or more plants from outside the United States? A) 0.4242 B) 0.3776 C) 0.3523 D) 0.4696

Q: Which of the following is true of a typical functional organization? a. It eliminates duplication of resources. b. It makes communication across the organization easier and smooth. c. A project cuts across organizational boundaries in a typical functional organization. d. Team members are assigned exclusively to projects in a typical functional organization.

Q: Which of the following is true of the Critical Path Method (CPM)? a. It allows us to investigate the effects of uncertainty of activity times on project completion times. b. It uses the variance in the critical path activities to evaluate the risks associated with project completion times. c. It assumes that activities are independent of one another, with clearly defined start and finish dates. d. It accounts for the interruptions that may affect an activity between the start and the finish times.

Q: In the project management life cycle, the _____ stage involves collecting and assessing status reports, managing changes to baselines, and responding to circumstances that can negatively impact the project participants. a. closing b. planning c. organizing d. controlling

Q: A population of 10 items contains 3 that are red and 7 that are green. What is the probability that in a random sample of 3 items selected without replacement, 2 red and 1 green items are selected? A) 0.175 B) 0.086 C) 0.124 D) 0.211

Q: Implementing a new computer-aided design system is an example of a project in the functional area of _____. a. engineering b. operations c. logistics d. marketing

Q: Consider a situation in which a used-car lot contains five Fords, four General Motors (GM) cars, and five Toyotas. If five cars are selected at random to be placed on a special sale, what is the probability that three are Fords and two are GMs? A) 0.09 B) 0.03 C) 0.04 D) 0.06

Q: Rose is in charge of advertising a new product launched by her company. She has defined the advertising for this product as an individual project that consists of seven activities. Following are the characteristics of these activities:ActivityImmediate Predecessor(s)Activity Time(in weeks)ANone2BNone2CA4DB5EC5FD2GE, F2Calculate the earliest completion time for the project using a Gantt chart.a. 10 weeksb. 11 weeksc. 12 weeksd. 13 weeks

Q: Arrivals to a bank automated teller machine (ATM) are distributed according to a Poisson distribution with a mean equal to three per 15 minutes. What is the probability that fewer than four customers will arrive in a 30-minute segment? A) 0.1512 B) 0.1889 C) 0.2515 D) 0.2576

Q: If an activity can be completed in 10 weeks at a cost of $3,200 instead of the normal time of 12 weeks at a cost of $2,400, then the crash cost per week for the given activity is _____. a. $200 b. $400 c. $600 d. $800

Q: In the context of the Critical Path Method (CPM), the slack time (ST) for an activity is computed as: a. the latest start (LS) time minus the earliest finish (EF) time. b. the latest finish (LF) time minus the earliest start (ES) time. c. the latest start (LS) time minus the earliest start (ES) time. d. the earliest finish (EF) time minus the latest start (LS) time.

Q: The mean number of errors per page made by a member of the word processing pool for a large company is thought to be 1.5 with the number of errors distributed according to a Poisson distribution. If three pages are examined, what is the probability that more than 3 errors will be observed? A) 0.6577 B) 0.6969 C) 0.7324 D) 0.7860

Q: Which of the following is an example of a project that belongs to the functional area of accounting and finance? a. Market research study b. Planning a firm's initial public offering c. Annual performance and compensation review d. Installing a revenue management system

Q: Dell Computers receives large shipments of microprocessors from Intel Corp. It must try to ensure the proportion of microprocessors that are defective is small. Suppose Dell decides to test five microprocessors out of a shipment of thousands of these microprocessors. Suppose that if at least one of the microprocessors is defective, the shipment is returned. Calculate the probability that the entire shipment will be kept by Dell even though the shipment has 10% defective microprocessors. A) 0.3995 B) 0.3979 C) 0.5905 D) 0.4550

Q: Which of the following is an assumption made by the critical path method (CPM)? a. The activity time estimates are accurate and stable. b. Activities are dependent on each other, without clearly defined start and finish times. c. Activities are interrupted many times before completion. d. The project network defines a tentative work sequence that can be changed anytime during the project.

Q: In the context of projects, _____ are discrete tasks that consume resources and time. a. value chains b. activities c. processes d. schedules

Q: Magic Valley Memorial Hospital administrators have recently received an internal audit report that indicates that 15% of all patient bills contain an error of one form or another. After spending considerable effort to improve the hospital's billing process, the administrators are convinced that things have improved. They believe that the new error rate is somewhere closer to 0.05.Suppose that recently the hospital randomly sampled 10 patient bills and conducted a thorough study to determine whether an error exists. It found 3 bills with errors. Assuming that managers are correct that they have improved the error rate to 0.05, what is the probability that they would find 3 or more errors in a sample of 10 bills? A) 0.0115 B) 0.0233 C) 0.0884 D) 0.0766

Q: A _____ is a temporary and often customized initiative that consists of many smaller tasks and activities that must be coordinated and completed to finish the entire initiative on time and within budget. a. resource plan b. schedule c. project d. product-process matrix

Q: Given a binomial distribution with n = 8 and p = 0.40, obtain the probability that the number of successes is within 2 standard deviations of the mean.A) 0.6887B) 0.7334C) 0.8665D) 0.9334

Q: The district magistrate of a city has decided to reconstruct the most frequented street of the city. He plans to block the street for the duration of the work, which will cause considerable inconvenience to the people of the city. The project has three parallel paths defined as the following: Path A-B-C-H will take 16 days. Path A-D-E-H will take 22 days. Path A-F-G-H will take 30 days. In the given scenario, which of the following statements is true? a. The expected duration of the project is 68 days. b. Activities B, D, and F have an earliest starting time of 0. c. Path A-D-E-H has the largest slack time. d. Path A-F-G-H is the critical path.

Q: The activities, their respective immediate predecessors, and activity times for a particular project are given in the table below. Determine the earliest completion time for this project using a Gantt chart.ActivityImmediate Predecessor(s)Activity Time(in weeks)ANone1BNone1CA4DB5EC, D5FE3GF2a. 14 weeksb. 16 weeksc. 18 weeksd. 20 weeks

Q: Which of the following is true of crashing a project? a. It involves the removal of resources from selected project activities to reduce costs. b. It increases the total cost of the project. c. It increases the total time taken to complete the project. d. It is a trade-off between project revenue and additional input costs.

Q: The calculation (a + 4m + b) / 6 is used to find _____ time. a. optimistic b. expected c. average d. pessimistic

Q: If a binomial distribution applies with a sample size of n = 20, find the standard deviation, n = 20, p = 0.20. A) 1.7889 B) 2.1889 C) 2.7889 D) 3.1221

Q: Which of the following stages of the project life cycle entails the scheduling of activities? a. The defining stage b. The planning stage c. The organizing stage d. The controlling stage

Q: The Project Evaluation and Review Technique (PERT) was developed as a means of scheduling and controlling projects with constant activity times.a. Trueb. False

Q: The only way the project completion time can be reduced is by crashing activities on the critical path. a. True b. False

Q: A pure project organizational structure eliminates the duplication of resources across the organization. a. True b. False

Q: For a binomial distribution with a sample size equal to 10 and a probability of a success equal to 0.30, what is the probability that the sample will contain exactly three successes? Use the binomial formula to determine the probability. A) 0.3277 B) 0.3288 C) 0.2668 D) 0.2577

Q: In the context of the Critical Path Method (CPM), latest start (LS) and latest finish (LF) times are computed by making a backward pass through the network, beginning with the ending project activity or activities. a. True b. False

Q: The manager for State Bank and Trust has recently examined the credit card account balances for the customers of her bank and found that 20% have an outstanding balance at the credit card limit. Suppose the manager randomly selects 15 customers and finds 4 that have balances at the limit. Assume that the properties of the binomial distribution apply. What is the probability that 4 or fewer customers in the sample will have balances at the limit of the credit card? A) 0.1876 B) 0.8358 C) 0.6482 D) 0.3832

Q: The earliest time that an activity can be completed is equal to the latest time it can begin minus the time to perform the activity. a. True b. False

Q: A key assumption with crashing is that the time can be reduced to any proportion of the crash time at a proportional increase in cost. a. True b. False

Q: Project managers do not need technical expertise. a. True b. False

Q: Cramer's Bar and Grille in Dallas can seat 130 people at a time. The manager has been gathering data on the number of minutes a party of four spends in the restaurant from the moment they are seated to when they pay the check. Number of Minutes Probability 60 0.05 70 0.15 80 0.20 90 0.45 100 0.10 110 0.05 What is the variance and standard deviation? A) Variance = 164.99, standard deviation = 12.84 B) Variance = 233.75, standard deviation = 15.89 C) Variance = 128.75, standard deviation = 11.35 D) Variance = 134.75, standard deviation = 11.61

Q: Indicate whether the statement is true or false.The Critical Path Method (CPM) allows us to investigate the effects of uncertainty of activity times on the project completion time.a. Trueb. False

Q: Jennings Assembly in Hartford, Connecticut, uses a component supplied by a company in Brazil. The component is expensive to carry in inventory and consequently is not always available in stock when requested. Furthermore, shipping schedules are such that the lead time for transportation of the component is not a constant. Using historical records, the manufacturing firm has developed the following probability distribution for the product's lead time. The distribution is shown here, where the random variable is the number of days between the placement of the replenishment order and the receipt of the item. x P(x) 2 0.15 3 0.45 4 0.30 5 0.0.75 6 0.025 What is the coefficient of variation for delivery lead time? A) 38.461% B) 27.065% C) 27.891% D) 31.772%

Q: The equation used to calculate the number of Kanban cards required in a system is , where α denotes _____.a. the demand during lead timeb. a form of safety stockc. capacity utilizationd. the reorder point

Q: A hinge manufacturing company employs a Kanban system for a component part. The daily demand is 900 hinges. Each container has a waiting time of 0.05 days and a processing time of 0.37 days. The container size is 60 hinges, and the safety factor (α) is 10 percent. Given this data, the number of Kanbans necessary for the system is: a. less than 4 Kanbans. b. more than 4 but less than or equal to 8 Kanbans. c. more than 8 but less than or equal to 12 Kanbans. d. more than 12 but less than or equal to 16 Kanbans.

Q: _____ is focused on ensuring that operating systems will perform their intended function reliably. a. Total productive maintenance b. A just-in-time system c. An intermittent production system d. Total quality management

Q: The U.S. Census Bureau (Annual Social & Economic Supplement) collects demographics concerning the number of people in families per household. Assume the distribution of the number of people per household is shown in the following table: x P(x) 2 0.27 3 0.25 4 0.28 5 0.13 6 0.04 7 0.03 Compute the variance and standard deviation of the number of people in families per household. A) Variance=1.6499, standard deviation=1.2845 B) Variance=1.2845, standard deviation=1.6499 C) Variance=6.7182, standard deviation=2.5919 D) Variance=2.5919, standard deviation=6.7182

Q: In the airline industry, short setup and turnaround time translates into _____. a. idle time b. fewer service encounters c. overproduction d. higher asset utilization

Q: In the context of the major categories of waste classified by the Toyota Motor Company, which of the following is true of overproduction? a. It ties up production facilities, and the resulting excess inventory simply sits idle. b. It is waste associated with the expense of idle stock and extra storage. c. It allows queues to build up between operations, resulting in longer lead times. d. It is a result of inefficient workplace design and location of tools and materials.

Q: The roll of a pair of dice has the following probability distribution, where the random variable is the sum of the values produced by each die: x P(x) 2 1/36 3 2/36 4 3/36 5 4/36 6 5/36 7 6/36 8 5/36 9 4/36 10 3/36 11 2/36 12 1/36 Calculate the standard deviation of x. A) 3.415 B) 2.333 C) 3.125 D) 2.415

Q: A manufacturer of automobile engines is designing a new Kanban system for engine #321. The demand for #321 is 75 parts per day, and the container can hold 8 parts at a time. The total processing and waiting time is 3 days. The manager wants a safety factor (α) of 2 or 200 percent. How many Kanbans are required in this system? a. 85 b. 90 c. 100 d. 115

Q: Quickly changing tooling and fixtures to reduce setup time and achieve higher flexibility and productivity is the principle of _____. a. Kanban b. andon c. the 5Ss d. SMED

Q: Which of the following is a difference between lean production and Six Sigma? a. The lean production technique can be used in nonmanufacturing environments, whereas Six Sigma cannot be used in nonmanufacturing environments. b. Lean production addresses less visible problems in processes, whereas Six Sigma is more concerned with visible problems. c. Lean production is focused on effectiveness by reducing errors and defects, whereas Six Sigma is focused on efficiency by reducing waste and improving process flow. d. Lean production tools are more intuitive and easier to apply by anybody in the workplace, whereas many Six Sigma tools require advanced training and expertise of specialists.

Q: Because of bad weather, the number of days next week that the captain of a charter fishing boat can leave port is uncertain. Let x = number of days that the boat is able to leave port per week. The following probability distribution for the variable, x, was determined based on historical data when the weather was poor: x P(x) 0 0.05 1 0.10 2 0.10 3 0.20 4 0.20 5 0.15 6 0.15 7 0.05 Based on the probability distribution, what is the expected number of days per week the captain can leave port? A) 3.7 B) 4.5 C) 2.8 D) 1.7

Q: The random variable x is the number of customers arriving at the service desk of a local car dealership over an interval of 10 minutes. It is known that the average number of arrivals in 10 minutes is 5.3. The probability that there are less than 3 arrivals in any 10 minutes is: A) .0659 B) .0948 C) .1016 D) .1239

Q: A _____ system produces finished-goods inventory in advance of customer demand using a forecast of sales. a. just-in-time b. push c. Kanban d. pull

Q: A local paint store carries 4 brands of paint (W, X, Y, and Z). The store has 5 cans of W, 3 cans of X, 6 cans of Y, and 15 cans of Z, all in white. It is thought that customers have no preference for one of these brands over another. If this is the case, what is the probability that the next 5 customers will select 1 can of W, X, Y and 2 cans of brand Z? A) About .23 B) Approximately .08 C) Over .30 D) 0.25

Q: Which of the following is a similarity between lean production and Six Sigma? a. Both solely address visible problems in processes. b. Both focus on efficiency by reducing waste and improving process flow. c. Both are driven by customer requirements. d. Both focus on problems related to variation in performance.

Q: A small city has two taxi companies (A and B). Each taxi company has 5 taxis. A motel has told these companies that they will randomly select a taxi company when one of its customers needs a cab. This morning 3 cabs were needed. Assuming that no one individual taxi can be used more than once, what is the probability that 2 of the cabs selected will be from Company A and the other will be from B? A) 0.417 B) 0.25 C) 0.583 D) 0.5

Q: Drive-in-Style Motors follows a traditional manufacturing system. It produces a fixed number of cars every month. It is now planning to switch to a system of manufacturing where workers go to the source of required parts and withdraw them based on requirements. In this scenario, which of the following is most likely to occur if Drive-in-Style Motors implements this plan? a. Its inventory levels will increase significantly when the demand is low. b. Its component parts and subassemblies will be replenished only when needed. c. Its finished goods inventory will decrease, but raw materials and work-in-process inventories will increase. d. Its workers, at any given process, will produce units before they are needed.

Q: The hypergeometric probability distribution is used rather than the binomial or the Poisson when: A) the sampling is performed with replacement. B) the sampling is performed without replacement from an infinite population. C) the sampling is performed without replacement from a finite population. D) the sampling is performed with replacement from a finite population.

Q: In the context of the 5S principles, _____ means to keep a process going through training, communication, and organizational structures. a. shine b. sort c. sustain d. standardize

Q: If a distribution is considered to be Poisson with a mean equal to 11, the most frequently occurring value for the random variable will be: A) 10.5 B) 11 C) 10 and 11 D) 22

Q: Create & Sell Manufacturing Inc. uses a Kanban system for a component. The daily demand is 175 units. Each container has a combined waiting and processing time of 0.20 days. If the container size is 10 brackets and the safety factor is 11 percent, how many Kanban card sets should be authorized? a. 2 b. 4 c. 6 d. 7

Q: If the standard deviation for a Poisson distribution is known to be 3, the expected value of that Poison distribution is: A) 3 B) about 1.73 C) 9 D) Can't be determined without more information.

Q: Which of the following is not true about lean principles? a. Lean manufacturing plants look significantly different from traditional plants. b. They are always transferable to front-office services that involve high customer contact. c. Lean manufacturing plants use multi-skilled workers who perform both direct and indirect work. d. In the airline industry, idle time is the largest form of waste.

Q: The manager of a movie theater has determined that the distribution of customers arriving at the concession stand is Poisson distributed with a standard deviation equal to 2 people per 10 minutes. What is the probability that 0 customers arrive during a 10-minute period?A) 0.1353B) 0.0183C) 0.9817D) Essentially 0

Q: In the context of lean tools and approaches, _____ are indicators for operating activities that are placed in plain sight of all employees so that everyone can quickly and easily understand the status and performance of the work system. a. Kanban cards b. push systems c. pull systems d. visual controls

Q: A company is using a Kanban system with 2 containers, each holding 50 parts, between a downstream (using) and an upstream (producing) work center. The using work center can handle 250 jobs per day. The average elapsed time for the entire cycle is currently 0.25 days. The company is concerned about the safety factor for the operation. Which of the following is the safety factor (α) of the current operation? a. 20 percent b. 60 percent c. 80 percent d. 40 percent

Q: Which of the following statements is true with respect to a Poisson distribution? A) The Poisson distribution is symmetrical when the mean is close to 5. B) The Poisson distribution is more right-skewed for smaller values of the mean. C) The variance of the Poisson distribution is equal to the square root of the expected value. D) The Poisson distribution is an example of a continuous probability distribution.