Concept explainers
A
Interpretation: The number of dentists required to confirm that any patient does not spend more than 15 minutes needs to be calculated.
Concept Introduction: Utilization rate is average the time spend by a person in productivity activity. It is calculated as percentage.
B
Interpretation: Change in operating characteristics after a fourth dentist is placed should be calculated.
Concept Introduction: Utilization rate is average the time spent by a person in productivity activity. It is calculated as the percentage.
C
Interpretation: Change in operating characteristics after a fifth dentist is placed should be calculated.
Concept Introduction: Utilization rate is average the time spent by a person in productivity activity. It is calculated as the percentage.
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Operations Management: Processes and Supply Chains (12th Edition) (What's New in Operations Management)
- During nearly four decades of business operations, Memphis-based FedEx has earned a reputation for reliable, on-time delivery of packages to homes and offices around the country. Founder Fred Smith originally focused on overnight deliveries, choosing Memphis as the company’s headquarters because the airport rarely closes due to bad weather. With FedEx’s planes departing and arriving on schedule nearly all the time, its express shipments usually remained on schedule, then and now. To reassure customers that delivery will take place when and where promised, the firm offers a money-back guarantee on time-sensitive express shipments, among other services. FedEx has steadily expanded its portfolio of services since the 1970s. Its original overnight express delivery is currently available to U.S. customers in various forms, including “first-overnight” delivery, next-morning delivery, next-afternoon delivery, and budget-pleasing two- or three-day delivery. The company’s services also include cost-effective ground delivery for parcels and extra-speedy same-day delivery for urgent deliveries within 1,800 cities. Over the years, FedEx has widened its delivery network to more than 220 countries. It has purchased more cargo jets and acquired specialized shipping firms, including Tiger International, Roberts Express, RPS, and TNT Express, to support global growth. For international business customers needing products, parts, or raw materials shipped across countries or continents, the company now offers time-saving services such as commercial freight forwarding and cross-border logistical support. To add the convenience of local drop-off and pickup points for U.S. consumers and small businesses, FedEx acquired the Kinko’s office services company in 2004 and later rebranded it as FedEx Office. This acquisition also added printing and copying to the menu of services offered. Then the company arranged for large U.S. retailers such as Walgreens, Albertsons, Kroger, and Safeway to accept packages for shipment and receive package delivery for customer pickup in thousands of store locations. This means people who want to send a package can head to a nearby retailer and ship where they shop, rather than making a separate trip to the FedEx location. It’s also a safe alternative for packages to be picked up by people who don’t want FedEx shipments left by the front door. Another service FedEx offers to small and mid-sized businesses, including retailers, is FedEx Fulfillment. The purpose is to expedite order fulfillment by having each business store its products in a FedEx warehouse. Then, when the business’s customers place orders, FedEx puts the products into boxes bearing the business’s own logo and ships directly to those customers. The business doesn’t need a separate warehouse or staff for fulfillment, and packages are on their way to customers more quickly because the products were in FedEx’s warehouse, ready to be packed and shipped. This service puts FedEx into direct competition with Amazon.com, which offers a similar service to merchants that sell through the online Amazon Marketplace. But it also gives businesses that don’t sell via Amazon a fast and professional fulfillment alternative. FedEx is careful to let customers know, through media and social-media announcements, when it anticipates that extreme weather or other conditions will cause delays or force it to halt pickups and deliveries. For the duration of Hurricane Irma, for example, FedEx said it would suspend deliveries in Florida. Some Florida customers who had ordered generators to be delivered via FedEx were unhappy, because they worried about being without power during and after the storm. But one FedEx employee loaded several generator orders into his car and took them to customers himself. When a customer posted a grateful compliment to FedEx on Facebook, the message generated thousands of likes, shares, and positive comments. The company also received positive comments for its donations of cash and transportation services to areas devastated by Hurricanes Irma, Harvey, and Maria. According to the American Customer Satisfaction Index (ACSI), FedEx often tops the list of U.S. shipping companies as ranked by customers surveyed. Every day, the company delivers 13 million packages—and during the busy year-end holiday season, it delivers many more. By meeting customers’ expectations for on-time deliveries, FedEx has increased annual revenues beyond $60 billion and positioned itself for continued growth in the future. How does FedEx’s money-back guarantee address customers’ concerns about heterogeneity?arrow_forwardPatients arrive at a dentist’s office with an arrival rate of 2.8 patients per hour. The dentist can treat patients at a service rate of 3 patients per hour. A study of patient waiting times shows that a patient waits an average of 30 minutes before seeing the dentist. Note the M/M/1 model does not necessarily apply here. What are the arrival and service rates in terms of patients per minute? What is the average number of patients in the waiting room? If a patient arrives at 10:10am, at what time is the patient expected to leave the office?arrow_forwardThe Escargot is a small French restaurant with six waiters and waitresses. The average service time at the restaurant for a table (of any size) is 85 minutes (Poisson distributed). The restaurant does not take reservations, and parties arrive for dinner (and stay and wait) every 18 minutes (negative exponential distribution). The restaurant owner is concerned that a lengthy waiting time might hurt its business in the long run. What are the current waiting time and queue length for the restaurant? Discuss the business implications of the current waiting time and any actions the restaurant owner might take.arrow_forward
- One field representative services five customers for a computer manufacturer. Customers request assistance at an average (Poisson-distributed) rate of once every four working days. The field representative can handle an average (Poisson-distributed) of one call per day. Determine: Use Table 1. a. The expected number of customers waiting. (Round your answer to 3 decimal places.) Expected number of customers waiting b. The average length of time customers must wait from the initial request for service until the service has been completed. (Round your answer to 2 decimal places.) Average length of time days c. The percentage of time the service rep will be idle. (Round your answer to 1 decimal place.) Percentage of Idle time d. By how much would your answer to part a be reduced if a second field rep were added? (Round your answer to 3 decimal places.) Reduced number of customer(s) Please answer part Carrow_forward9. Marty's Barber Shop has one barber. Customers have an arrival rate of 2.2 customers per hour, and haircuts are given with a service rate of 5 per hour. Use the Poisson arrivals and exponential service times model to answer the following questions: a. What is the probability that no units are in the system? b. What is the probability that one customer is receiving a haircut and no one is waiting? What is the probability that one customer is receiving a haircut and one customer is waiting? C. d. What is the probability that one customer is receiving a haircut and two customers are waiting? e. What is the probability that more than two customers are waiting? f. What is the average time a customer waits for service?arrow_forwardPatients arrive to a small hospital emergency room according to a Poisson process with an average rate of 1.5 per hour. Because service times for these patients vary considerably, the service times are accurately described by an exponential distribution. Suppose that the average service time is 26 minutes. If there is only a single doctor working at any point in time, find the following measures of service for this emergency room: The expected total time in the system. b. The expected time each customer has to wait. c. The expected number of patients waiting for service. d. If the emergency room has a triage nurse who gives priority to more serious conditions, explain qualitatively how that would change your results to parts a, b, and c. What additional information would one need to know to analyze a system like this?arrow_forward
- Customers of Golden Crust Bakery arrive at the single cashier at the rate of 10 per hour. The average service time for the cashier is five minutes. Arrivals follow a Poisson distribution, and service times follow an exponential distribution. a. What is the average utilization of the cashier? b. What is the average number of customers in the system? c. What is the average number of customers in line? What is the average time spent in the system? e. What is the average time spent in line? d.arrow_forwardGiven information: A typical TSA agent at Piedmont Triad International Airport takes approximately 1.15 minutes to screen each passenger that arrives at the security gate. During the day, a passenger arrives at the gate on average every 1.3 minutes. Both the service rate and arrival rate follow a Poisson distribution. Based on this information and the assumption that only one screening line is open at the security gate, answers the following questions. Round calculations to at least 3 decimal places. Note: Round each calculation to at least 3 decimal places. Arrival time =60/1.3=46.153 Server Rate =60/1.15=52.174 L=expected number of passengers in queue =6.780 waiting time in queue =.1469 time spent screening=.1660 please answer the 2 foloowing questions What is percent of the time does the typical TSA agent spend actively screening passengers? Throughout the day, passenger arrival rates vary with the greatest number of passengers arriving about 45 minutes before a flight is…arrow_forwardFor each of the following queuing systems, indicate whether it is a single or multiple-server model, the queue discipline, and whether it’s calling population is infinite or finite. Hair salon Bank Laundromat Doctor’s office Advisor’s office Airport runway Service station Copy centre Team trainer Mainframe computerarrow_forward
- A branch office of a large engineering firm has one on-line terminal connected to a central computer system for 16 hours each day. Engineers drive to the branch office to use the terminal to make routine calculations with an average exponential distribution of 30 minutes per use. The daily arrival pattern of engineers is random (Poisson) with an average of 20 persons. The branch manager is starting to receive complaints from the engineers about the length of time many of them have to wait to use the terminal. Question: 1. What is and u measured in per hour intervals? 2. On the average, how many minutes does each engineer have to wait? 3. Using increments of 0.1 hours, what would be the least value of u so that the waiting time will be not exceed 30 minutes?arrow_forwardThe local Division of Motor Vehicles (DMV) is concerned with its waiting line system. Currently, the DMV uses a single-server, single-line, single-phase system when processing license renewals. Based on historical evidence, the average number of customers arriving per hour is 9 and is described by a Poisson distribution. The service rate is 12 customers per hour with the service times following an exponential distribution. The customers are patient and come from an infinite population. The manager of the DMV would like you to calculate the operational characteristics of the waiting line system.(a) What is the average system utilization? (b) What is the average number of customers in the system? (c) What is the average number of customers waiting in line? (d) What is the average time a customer spends in the system? (e) What is the average time a customer spends waiting in line?arrow_forwardBenny the Barber owns a one-chair shop. At barber college, they told Benny that his customers would exhibit a Poisson arrival distribution and that he would provide an exponential service distribution. His market survey data indicate that customers arrive at a rate of two per hour. It will take Benny an average of 20 minutes to give a haircut. Based on these figures, find the following: Part (a): The average number of customers waiting. Arrival Time, λ =2 customers per hour Service Time, μ = 20 minute, or 60/20= 3 customer per hour Lq = (2)2 / 3*(3-2) = 1.333 customers Part (b): The average time a customer waits. Wq= 1.333/2=0,665 \~ 0,67 or 40 minutes Part (c): The average time a customer is in the shop. LS = 2/ 3-2 =2 customers. WS = 2/2 = 1 hour Part (d): The average utilization of Benny’s time. P= λ/ μ = 2/3=0,666 percent ~ 0,67 % Benny the Barber (see Question 1) is considering the addition of a second chair. Customers would be selected for a haircut on a FCFS basis from…arrow_forward
- Practical Management ScienceOperations ManagementISBN:9781337406659Author:WINSTON, Wayne L.Publisher:Cengage,MarketingMarketingISBN:9780357033791Author:Pride, William MPublisher:South Western Educational Publishing