DSCI 304 Quiz 1 CH. 2

For the purpose of process analysis, which of the following measures would be considered an appropriate flow unit for analyzing the main operation of a gas station?

- Sales dollars - Number of customers served - Number of gasoline pumps - Number of employees

LaVilla is a village in the Italian Alps. Given its enormous popularity among Swiss, German, Austrian, and Italian skiers, all of its beds are always booked in the winter season and there are, on average, 1200 skiers in the village. On average, skiers stay in LaVilla for 10 days. How many new skiers are arriving, on average, in LaVilla every day?

1,200 beds divided by 10 days = 120 new skiers per day.

LaVilla is a village in the Italian Alps. Given its enormous popularity among Swiss, German, Austrian, and Italian skiers, all of its beds are always booked in the winter season and there are, on average, 1,400 skiers in the village. On average, skiers stay in LaVilla for 9 days. How many new skiers are arriving, on average, in LaVilla every day?

1,400 beds divided by 9 days = 156 new skiers per day.

One of the chair lifts at a ski resort unloads 1,500 skiers per hour at the top of the slope. The ride from the bottom to the top takes 13 minutes. How many skiers are riding on the lift at any given time?

1,500 skiers divided by 60 minutes per hour (flow rate) × 13 minutes (flow time) = 325 skiers

One of the chair lifts at a ski resort unloads 1,800 skiers per hour at the top of the slope. The ride from the bottom to the top takes 12 minutes. How many skiers are riding on the lift at any given time?

1,800 skiers divided by 60 minutes per hour (flow rate) × 12 minutes (flow time) = 360 skiers

A Rhode Island company produces communion wafers for churches around the country and the world. The little company produces a lot of wafers, several hundred million per year. When in production, the process produces wafers at the rate of 100 per second. During this production process, the wafers must spend 15 minutes passing through a cooling tube. How many wafers does the cooling tube hold, on average, when in production (in other words, don't count the time they are not in production)?

100 per second × 60 seconds per minute × 15 minutes = 90,000

A consulting company must hire 15 new associates per year to replace those who have left the company for other positions or have retired. The company employs 120 associates overall. How long is the average associate employed at the consulting company?

120 associates = 15 new employees × flow time. Flow time = 8

A consulting company must hire 13 new associates per year to replace those who have left the company for other positions or have retired. The company employs 129 associates overall. How long is the average associate employed at the consulting company?

13 associates = 129 new employees × flow time. Flow time = 9.9

Patients take a drug for severe acne for 2 months and there are 130,000 new patients each month. How many patients are taking this drug on average at any given time?

2 months (flow time) × 130,000 new patients per month = 260,000 patients

A large-scale bakery is laying out a new production process for its packaged bread, which it sells to several grocery chains. It takes 12 minutes to bake the bread. How large of an oven is required so that the company is able to produce 4200 units of bread per hour (measured in the number of units that can be baked simultaneously)?

4,200 units multiplied by (12 minutes / 60 minutes) = 840 units

A large-scale bakery is laying out a new production process for its packaged bread, which it sells to several grocery chains. It takes 24 minutes to bake the bread. How large of an oven is required so that the company is able to produce 4200 units of bread per hour (measured in the number of units that can be baked simultaneously)?

4,200 units multiplied by (24 minutes / 60 minutes) = 1,680 units

Over the course of a 24-hour period a call center handled 1200 different calls and at noon there were 50 callers "in" the center (talking or waiting to talk to a representative). The sixth caller of the day spent 2.5 minutes with a representative. Which of the given numbers is an inventory?

50 callers is an inventory.

Patients take a drug for severe acne for 6 months and there are 150,000 new patients each month. How many patients are taking this drug on average at any given time?

6 months (flow time) × 150,000 new patients per month = 900,000 patients

The table below provides the time stamps for the 8 people who called a reservation desk for a ferry service between 8:00 am and 8:35 am. Based on the data in the table, what is the flow rate of callers? Caller Time in Time out 1 8:00 8:11 2 8:00 8:16 3 8:03 8:18 4 8:08 8:23 5 8:10 8:27 6 8:15 8:33 7 8:17 8:27 8 8:17 8:30

8 calls divided by 35 minutes = 0.2 calls per minute.

A Rhode Island company produces communion wafers for churches around the country and the world. The little company produces a lot of wafers, several hundred million per year. When in production, the process produces wafers at the rate of 87 per second. During this production process, the wafers must spend 13 minutes passing through a cooling tube. How many wafers does the cooling tube hold, on average, when in production (in other words, don't count the time they are not in production)?

87 per second × 60 seconds per minute × 13 minutes = 67,860

Six customers enter a gift shop during a 3-hour period. On average there are 0.25 customers in the gift shop and each spends 7.5 minutes in the shop on average. Which of the following numbers is most directly associated with the flow rate of customers?

A rate is given in flow units per unit of time, as in six customers over 3-hours.

If you maintain inventory at a constant level and keep the throughput rate constant:

Customer delivery dates become more reliable

A computer server experiences large fluctuations in the amount of data requests it receives throughout the day. Because of this variation, Little's Law does not apply.

False

Throughput, sometimes referred to as output rate, is expressed in units produced per hour.

False

Little's Law is very general, so it is not necessary that flow rate and flow time use the same time units.

False: The same time units must be used for the flow rate and the flow time.

Forty customers per 90 minutes is a(n) ______

Flow rate

The table below shows the time stamps of 10 customers who visited a local bank branch from 9:00 a.m. to 10:00 a.m. What is the flow rate of customers? Customer Time in Time out 1 9:01 9:07 2 9:06 9:21 3 9:08 9:20 4 9:14 9:19 5 9:20 9:28 6 9:26 9:33 7 9:31 9:39 8 9:40 9:46 9 9:44 9:59 10 9:53 9:57

Flow rate = 10 customers divided by 60 minutes = 0.1667

Last year, there were 2,700,000 visitors to a national park and, on average, each visitor spent 17 hours in the park each day. Last year, on average, how many visitors were in the park each day? Assume the park is open 365 days per year.

Flow rate = 2,700,000 visitors divided by 365 days = 7,397.2603 visitors per day Flow time = 17 hours / 24 hours per day = 0.7083 days Inventory = 7,397.2603 (flow rate) × 0.7083 (flow time) = 5,240 visitors per day

CodeDeskInc matches programmers with freelance jobs. It has 25 employees who staff its online chat room. It receives, on average, 210 chat requests per hour, and the average chat session takes 5 minutes to complete (i.e., from start to finish). On average, how many chat sessions are active (i.e., started but not completed)?

Flow rate = 210 chats divided by 25 employees = 8.40 Flow time = 5 minutes divided by 60 minutes = 0.083 hour Inventory = Flow Rate × Flow Time, 8.40 × 0.083 = 0.7000 × 25 employees = 18 chats

CodeDeskInc matches programmers with freelance jobs. It has 30 employees who staff its online chat room. It receives, on average, 240 chat requests per hour, and the average chat session takes 5 minutes to complete (i.e., from start to finish). On average, how many chat sessions are active (i.e., started but not completed)?

Flow rate = 240 chats divided by 30 employees = 8 Flow time = 5 minutes divided by 60 minutes = 0.0833 hour Inventory = Flow Rate × Flow Time, 8 × 0.0833 = 0.6667 × 30 employees = 20 chats

Last year, there were 3,400,000 visitors to a national park and, on average, each visitor spent 22 hours in the park. Last year, on average, how many visitors were in the park?

Flow rate = 3,400,000 visitors divided by 365 days = 9,315 visitors per day Flow time = 22 hours / 24 hours per day = 0.9167 day Inventory = 9,315 (flow rate) × 0.9167 (flow time) = 8,539 visitors per day

The table below shows the time stamps of 10 customers who visited a local bank branch from 9:00 a.m. to 10:00 a.m. What is the flow time of customers? Customer Time in Time out 1 9:01 9:07 2 9:06 9:21 3 9:08 9:20 4 9:14 9:19 5 9:20 9:28 6 9:26 9:33 7 9:31 9:39 8 9:40 9:46 9 9:44 9:59 10 9:53 9:57

Flow time of customers = 8.6 minutes calculate the flow time of the customers, subtract the customers departure time from his or her arrival time. 86 total minutes divided by 10 customers = 8.6 minutes.

Little's Law states there is a relationship between:

Inventory Flow time Output Throughput

If inventory is measured in kilograms, then when applying Little's Law the flow rate can be measured in ______

Kilograms per second

Over the course of a month, which of the following is most likely to describe an appropriate flow unit for a process analysis of a hospital?

Number of Patients

From the perspective of process analysis, which of the following could be appropriate flow units for a hardware store?

Number of customers

For the purpose of process analysis, which of the following measures would be considered an appropriate flow unit for analyzing the main operation of a local accounting firm?

Number of tax returns completed

At a cruise ship terminal, each day on average 1000 passengers embark on ships. On average, passengers spend 5 days on their cruise before returning to this terminal. If the flow unit is a passenger, then what are the flow rate and flow time of this process?

The flow rate is 1,000 passengers per day and the flow time is 5 days.

It is election day and 1800 voters vote in their precinct's library during the 10 hours the polls are open. On average, there are 15 voters in the library and they spend on average 5 minutes in the library to complete their voting. What is the inventory of voters, the flow rate, and the flow time for each voter? Inventory of voters Flow rate Flow time

The flow rate is 1,800 / 10 = 180 per hour, or 180 / 60 = 3 per minute. The flow time is 5 minutes.

For the purpose of process analysis, which of the following measures would be considered an appropriate flow unit for analyzing the operation of a coffee shop?

The number of customers is the appropriate flow unit for process analysis. The employees are resources, and the other two measures are unlikely to change from week to week.

The table below provides the time stamps for the 8 people who called a reservation desk for a ferry service between 8:00 am and 8:20 am. Based on the data in the table, what is the flow time of callers? Caller Time in Time out 1 8:01 8:05 2 8:02 8:07 3 8:06 8:08 4 8:09 8:12 5 8:10 8:15 6 8:12. 8:20 7 8:16 8:19 8 8:17 8:19

To calculate the flow time of the callers, subtract the callers departure time from his or her arrival time. 32 total minutes divided by 8 callers = 4 minutes.

The table below shows the time stamps of 10 customers who visited a local bank branch from 9:00 a.m. to 9:45 a.m. What is the flow time of customers? Customer Time in Time out 1 9:2 9:11 2 9:2 9:8 3 9:4 9:34 4 9:7 9:18 5 9:8 9:33 6 9:10 9:18 7 9:14 9:37 8 9:19 9:45 9 9:19 9:45 10 9:24 9:44

To calculate the flow time of the customers, subtract the customers departure time from his or her arrival time. 184 total minutes divided by 10 customers = 18.4 minutes

A campus deli serves 325 customers over its busy lunch period from 11:30 a.m. to 1:30 p.m. A quick count of the number of customers waiting in line and being served by the sandwich makers shows that an average of 8 customers are in process at any point in time. What is the average amount of time that a customer spends in process? Average amount of time = ...

To solve this problem, use Little's Law. Inventory = Flow rate × Flow time. 8 people in line (average inventory) = 2.7083 flow rate × flow time The flow rate is 325 customers divided by 120 minutes = 2.7083 customers/minute Flow time = 8 / 2.7083 = 3 minutes

Consider the baggage check-in process of a small airline. Check-in data indicate that from 9 a.m. to 10 a.m., 220 passengers checked in. Moreover, based on counting the number of passengers waiting in line, airport management found that the average number of passengers waiting for check-in was 32. How long did the average passenger have to wait in line?

To solve this problem, use Little's Law. Inventory = Flow rate × Flow time. 32 people in line (average inventory) = 220 customers / 60 minutes (flow rate) × flow time. Flow time = 8.7 minutes

Consider the baggage check-in process of a small airline. Check-in data indicate that from 9 a.m. to 10 a.m., 240 passengers checked in. Moreover, based on counting the number of passengers waiting in line, airport management found that the average number of passengers waiting for check-in was 30. How long did the average passenger have to wait in line?

To solve this problem, use Little's Law. Inventory = Flow rate × Flow time. 30 people in line (average inventory) = 240 customers / 60 minutes (flow rate) × flow time. Flow time = 7.5 minutes

A campus deli serves 300 customers over its busy lunch period from 11:30 a.m. to 1:30 p.m. A quick count of the number of customers waiting in line and being served by the sandwich makers shows that an average of 10 customers are in process at any point in time. What is the average amount of time that a customer spends in process? Average amount of time = ...

To solve this problem, use Little's Law. Inventory = Flow rate × Flow time. 10 people in line (average inventory) = 2.5 flow rate × flow time Flow time = 4 minutes The flow rate is 300 customers divided by 120 minutes = 2.5

Over the course of a day, fans pour into a NASCAR venue at the rate of 8,000 people per hour. The average rate at which fans leave the venue ______.

must be exactly 8,000 people per hour; The flow rate into a process must equal the flow rate out of a process.