Exam 12: Introduction to Simulation Using Risk Solver Platform

Which of the following probability distributions are associated with discrete outcomes?

Exhibit 12.3 The following questions use the information below. An auto parts store wants to simulate its inventory system for engine oil. The company has collected data on the shipping time for oil and the daily demand for cases of oil. A case of oil generates a $10 profit. Customers can buy oil at any auto parts store so there are no backorders (the company loses the sale and profit). The company orders 30 cases whenever the inventory position falls below the reorder point of 15 cases. Orders are placed at the beginning of the day and delivered at the beginning of the day so the oil is available on the arrival day. An average service level of 99% is desired. The following spreadsheets have been developed for this problem. The company has simulated 2 weeks of operation for their inventory system. The current level of on-hand inventory is 25 units and no orders are pending. -Using the information in Exhibit 12.3, what formula should go in cell H8 to determine if an order should be placed?

Exhibit 12.3 The following questions use the information below. An auto parts store wants to simulate its inventory system for engine oil. The company has collected data on the shipping time for oil and the daily demand for cases of oil. A case of oil generates a $10 profit. Customers can buy oil at any auto parts store so there are no backorders (the company loses the sale and profit). The company orders 30 cases whenever the inventory position falls below the reorder point of 15 cases. Orders are placed at the beginning of the day and delivered at the beginning of the day so the oil is available on the arrival day. An average service level of 99% is desired. The following spreadsheets have been developed for this problem. The company has simulated 2 weeks of operation for their inventory system. The current level of on-hand inventory is 25 units and no orders are pending. -Using the information in Exhibit 12.3, what Risk Solver Platform (RSP) function should be used for generating a random shipping time based on the Data spreadsheet distribution for shipping time?

Exhibit 12.1 The following questions use the information below. The owner of Fix-a-dent Auto Repair wants to study the growth of his business using simulation. He is interested in simulating the number of damaged cars and the amount of damage to the cars each month. He currently repairs 100 cars per month and feels this can vary uniformly between a decrease of as much as 3% and an increase of up to 5% (average change of 1%) over the previous months. The dollar value of the damage to the cars is a normally distributed random variable with a mean of $3,000 and a standard deviation of $500. The average repair bill has been increasing steadily over the years and the owner expects the mean repair bill will increase by 1% per month. You have created the following spreadsheet to simulate the problem. -Using the information in Exhibit 12.1, what Risk Solver Platform (RSP) function should go in cell B8 to compute the number of cars repaired in the first month?

A machine produces an average of 500 parts per day with a standard deviation of 10 parts. This is a normally distributed variable. The percent of defective parts ranges from 8-12%. Parts which need minor repair comprise 75% of the defective parts and cost $5 to repair. The rest of the defective parts cost $20 to repair. What formulas should go in cells B8:B15 to compute the daily cost of defective parts? A B C D E F 1 Initial Conditions: 2 Number of Parts: Average 500 Std dev 10 Normal 3 \% Defective Lo 8\% Hi 12\% Cont. Uniform 4 \% Minor Defects 75\% Constant 5 Cost of Minor Defect \ 5 Constant 6 Cost of Major Defect \ 20 Constant 7 8 Units Produced 500 9 \% Defective 8.2\% 10 Total \#Defective 41 11 \#With Minor Defects 31 12 Cost of Minor Defects \ 155 13 \#With Major Defects 10 14 Cost of Major Defects \ 200 15 Total Cost \ 355

Project 12.1- Monte Carlo Integration A common application of Monte Carlo simulation is to provide numerical approximations. One such application is to approximate the area under a curve, or Monte Carlo integration. The following figure represents such a curve, defined over the range of X = 0 to X = 13. Call the area under this curve A. Monte Carlo integration begins by overlaying on the curve of interest a region (call this region, B) whose area is easy to calculate (i.e., a box). Monte Carlo integration then involves the random generation of points in B and a determination of the percentage of these points that fall in A (i.e., fall below the curve). This percentage represents that portion of the area of B that is the area of A. Use Monte Carlo integration techniques to approximate the area under the curve. Use exact techniques to calculate the true area under the curve. How accurate is your approximation?

University Florists makes bouquets from a variety of materials. The Daily Special Bouquet is priced at $20. The florist assembles this bouquet each day from a variety of low cost flowers he buys from his flower supplier. The actual cost of flowers ranges uniformly from $2 to $7, with all intermediate values being equally likely. The florist (who studied management science many years ago) knows that the time to assemble a bouquet is normally distributed with a mean time of 5 minutes and standard deviation of 1 minute. This will be the time required for all of the Daily Special Bouquets for that day. The florist values his labor time at $10 per hour. Sales are normally distributed with a mean of 10 bouquets per day with a standard deviation of 1 bouquet. What formulas should go in cells B8:B14 to simulate daily profits for the store?

An office supply store wants to simulate its inventory system for notebooks. The company has collected data on the shipping time and daily demand for notebooks. Each notebook generates a $2 profit. Customers can buy notebooks at any office supply store so there are no backorders (the company loses the sale and profit). The company orders 200 notebooks whenever the inventory position falls below the reorder point of 100 notebooks. Orders are placed at the beginning of the day and delivered at the beginning of the day so the notebooks are available on the arrival day. The average daily demand is 23.5 notebooks. An average service level of 99% is desired. There are currently 25 notebooks on hand and no orders are pending. The following spreadsheets have been developed for this problem. The company has simulated 1 month of operation for its inventory system. (HINT: This covers Rows 8 to 37 of the spreadsheet.) What formulas go in cells A1:J37 of the "Model" worksheet for this simulation?

Exhibit 12.4. The following questions use the information below. The manager of a Washington, DC sightseeing tour company is concerned about overbooking for one of his bus tours. The bus has 15 seats but sometimes there are empty seats. His records show that about 20% of ticket holders do not show up for their tour. Tickets cost $10 and are non-refundable. If the manager overbooks the tour and more than 15 passengers show up, some of them will be bumped to a later tour. This bumping costs the company $25 in various expenses to keep the customer happy until the next tour. The manager wants to see what happens to profits if 18 reservations are accepted. -Using the information in Exhibit 12.4, what formula should go in cell C13 of the worksheet to determine the Opportunity Cost of Empty Seats?

Exhibit 12.1 The following questions use the information below. The owner of Fix-a-dent Auto Repair wants to study the growth of his business using simulation. He is interested in simulating the number of damaged cars and the amount of damage to the cars each month. He currently repairs 100 cars per month and feels this can vary uniformly between a decrease of as much as 3% and an increase of up to 5% (average change of 1%) over the previous months. The dollar value of the damage to the cars is a normally distributed random variable with a mean of $3,000 and a standard deviation of $500. The average repair bill has been increasing steadily over the years and the owner expects the mean repair bill will increase by 1% per month. You have created the following spreadsheet to simulate the problem. -Using the information in Exhibit 12.1, what formula should go cell G5 to calculate the 80^th percentile of the empirical distribution of income?

Exhibit 12.3 The following questions use the information below. An auto parts store wants to simulate its inventory system for engine oil. The company has collected data on the shipping time for oil and the daily demand for cases of oil. A case of oil generates a $10 profit. Customers can buy oil at any auto parts store so there are no backorders (the company loses the sale and profit). The company orders 30 cases whenever the inventory position falls below the reorder point of 15 cases. Orders are placed at the beginning of the day and delivered at the beginning of the day so the oil is available on the arrival day. An average service level of 99% is desired. The following spreadsheets have been developed for this problem. The company has simulated 2 weeks of operation for their inventory system. The current level of on-hand inventory is 25 units and no orders are pending. -Using the information in Exhibit 12.3, what Risk Solver Platform (RSP) function should be used in cell D8 and copied to cells D9:D21 of the MODEL sheet to compute daily demand?

The Risk Solver Platform (RSP) is a good simulation tool because

What is the probability that 3 or more phone calls are received in any hour of operation? 1 \# of phone calls (\# of phone calls) \# of phone calls (\# of phone calls) 2 1 0.10 1 0.10 2 2 0.40 2 0.50 4 3 0.30 3 0.80 5 4 0.15 4 0.95 6 5 0.05 5 1.00

Simulation is used to

What is the correct Risk Solver Platform (RSP) function for generating random numbers from the following distribution on the number of children in families (assume a reference to the current worksheet). A B 1 \# of children P(\# af children) 2 1 0.20 3 2 0.30 4 3 0.25 5 4 0.20 6 5 0.05

Exhibit 12.3 The following questions use the information below. An auto parts store wants to simulate its inventory system for engine oil. The company has collected data on the shipping time for oil and the daily demand for cases of oil. A case of oil generates a $10 profit. Customers can buy oil at any auto parts store so there are no backorders (the company loses the sale and profit). The company orders 30 cases whenever the inventory position falls below the reorder point of 15 cases. Orders are placed at the beginning of the day and delivered at the beginning of the day so the oil is available on the arrival day. An average service level of 99% is desired. The following spreadsheets have been developed for this problem. The company has simulated 2 weeks of operation for their inventory system. The current level of on-hand inventory is 25 units and no orders are pending. -Using the information in Exhibit 12.3, what Risk Solver Platform (RSP) function should be used in cell I8 to determine the lead time for an order?

Exhibit 12.3 The following questions use the information below. An auto parts store wants to simulate its inventory system for engine oil. The company has collected data on the shipping time for oil and the daily demand for cases of oil. A case of oil generates a $10 profit. Customers can buy oil at any auto parts store so there are no backorders (the company loses the sale and profit). The company orders 30 cases whenever the inventory position falls below the reorder point of 15 cases. Orders are placed at the beginning of the day and delivered at the beginning of the day so the oil is available on the arrival day. An average service level of 99% is desired. The following spreadsheets have been developed for this problem. The company has simulated 2 weeks of operation for their inventory system. The current level of on-hand inventory is 25 units and no orders are pending. -Using the information in Exhibit 12.3, what formula should go in cell G9 to compute inventory position?

Exhibit 12.5 The following questions use the information below. The owner of Sal's Italian Restaurant wants to study the growth of his business using simulation. He is interested in simulating the number of customers and the amount ordered by customers each month. He currently serves 1000 customers per month and feels this can vary uniformly between a decrease of as much as 5% and an increase of up to 9%. The bill for each customer is a normally distributed random variable with a mean of $20 and a standard deviation of $5. The average order has been increasing steadily over the years and the owner expects the mean order will increase by 2% per month. You have created the following spreadsheet to simulate the problem. -The spreadsheet model for Sal, from Exhibit 12.5, has been run 300 times to produce the following output. What is the best case scenario for Sal based on this output? Simulation Statistics Name Income/Revenue Description Output Cell D21 Minimum= 211786.92 Maximum= 435002.74 Mean= 4119518.91 Std Deviation= 33831.44

What function should be used for generating random numbers from the following distribution on the number of phone calls per hour? 1 \# of phone calls (\# of phone calls) \# of phone calls (\# of phone calls) 2 1 0.10 1 0.10 2 2 0.40 2 0.50 4 3 0.30 3 0.80 5 4 0.15 4 0.95 6 5 0.05 5 1.00

Exhibit 12.3 The following questions use the information below. An auto parts store wants to simulate its inventory system for engine oil. The company has collected data on the shipping time for oil and the daily demand for cases of oil. A case of oil generates a $10 profit. Customers can buy oil at any auto parts store so there are no backorders (the company loses the sale and profit). The company orders 30 cases whenever the inventory position falls below the reorder point of 15 cases. Orders are placed at the beginning of the day and delivered at the beginning of the day so the oil is available on the arrival day. An average service level of 99% is desired. The following spreadsheets have been developed for this problem. The company has simulated 2 weeks of operation for their inventory system. The current level of on-hand inventory is 25 units and no orders are pending. -Using the information in Exhibit 12.3, what formula should go in cell H3 to compute the service level?