# Answer to problems from simulation, Probability, forecasting and decision theory

- Deterministic techniques assume that no uncertainty exists in model parameters.

True

False

Question 2

- A continuous random variable may assume only integer values within a given interval.

True

False

Question 3

- An inspector correctly identifies defective products 90% of the time. For the next 10 products, the probability that he makes fewer than 2 incorrect inspections is 0.736.
- True

False

Question 4

A decision tree is a diagram consisting of circles decision nodes, square probability nodes, and branches.

True

False

Question 5

- A table of random numbers must be normally distributed and efficiently generated.

True

False

Question 6

- Starting conditions have no impact on the validity of a simulation model.

True

False

Question 7

- The Delphi develops a consensus forecast about what will occur in the future.

True

False

Question 8

1. Qualitative methods are the least common type of forecasting method for the long-term strategic planning process.

True

False

Question 9

__________ is a measure of dispersion of random variable values about the expected value.

Standard deviation | ||

Range | ||

The z-score (the standard score) | ||

All of the above |

Question 10

- Assume that it takes a college student an average of 5 minutes to find a parking spot in the main parking lot. Assume also that this time is normally distributed with a standard deviation of 2 minutes. What time is exceeded by approximately 75% of the college students when trying to find a parking spot in the main parking lot?

Question 11

- The __________ is the maximum amount a decision maker would pay for additional information.

expected opportunity loss | ||

expected value | ||

expected value of perfect information | ||

none of the above |

Question 12

- In the Monte Carlo process, values for a random variable are generated by __________ a probability distribution.

Answer

sampling from | ||

running | ||

integrating | ||

implementing |

Question 13

- Pseudorandom numbers exhibit __________ in order to be considered truly random.

Answer

a limited number of possible outcomes | ||

a uniform distribution | ||

a detectable pattern | ||

a detectable run of certain numbers |

Question 14

- Two hundred simulation runs were completed using the probability of a machine breakdown from the table below. The average number of breakdowns from the simulation trials was 1.93 with a standard deviation of 0.20.

What is the probability of 2 or fewer breakdowns?

Question 15

- A seed value is a(n)

Answer

steady state solution of a simulation experiment | ||

number used to start a stream of random numbers | ||

first run of a simulation model | ||

analytic solution of a simulation experiment |

Question 16

- Consider the following demand and forecast.

If MAD = 2, what is the forecast for period 4?

Question 17

- rob

14, and 15)estion worth 2 points, 1 hour time limit (chapters 1,ue units EXCEPT:The U.S. Department of Agriculture estimates that the yearly yield of limes per acre is distributed as follows:The estimated average price per bushel is $16.80.

What is the expected yield of the crop?

425 | ||

442 | ||

440 | ||

475 |

Question 18

- Coefficient of determination is the percentage of the variation in the __________ variable that results from the __________ variable.

Answer

dependent, dependent | ||

independent, dependent | ||

dependent, independent | ||

independent, independent |

Question 19

- Which of the following possible values of alpha would cause exponential smoothing to respond the most
*slowly*to sudden changes in forecast errors?

Answer

.01 | ||

.10 | ||

.50 | ||

.90 |

Question 20

- __________ is absolute error as a percentage of demand.

Answer

Cumulative error | ||

MAD | ||

MAPD | ||

Average error |

Question 21

Consider the following graph of sales.

Which of the following characteristics is exhibited by the data?

Trend only | ||

Trend plus seasonal | ||

Seasonal only | ||

None of the above |

Question 22

- __________ is a category of statistical techniques that uses historical data to predict future behavior.

Answer

Qualitative methods | ||

Regression | ||

Time series | ||

Quantitative methods |

Question 23

- __________ is a linear regression model relating demand to time.

Linear trend | ||

Linear regression | ||

Forecast demand | ||

Linear equation |

Question 24

- In exponential smoothing, the closer alpha is to __________, the greater the reaction to the most recent demand.

-1 | ||

1 | ||

-1 or 1 |

Question 25

- An automotive center keeps tracks of customer complaints received each week. The probability distribution for complaints can be represented as a table or a graph, both shown below. The random variable xi represents the number of complaints, and p(xi) is the probability of receiving xi complaints.
What is the average number of complaints received per week? Round your answer to two places after the decimal.

Question 26

- A fair die is rolled 8 times. What is the probability that an even number (2,4, 6) will occur between 2 and 4 times? Round your answer to four places after the decimal.

Question 27

- A life insurance company wants to estimate their annual payouts. Assume that the probability distribution of the lifetimes of the participants is approximately a normal distribution with a mean of 68 years and a standard deviation of 4 years. What proportion of the plan recipients would receive payments beyond age 75? Round your answer to four places after the decimal.

Question 28

- A loaf of bread is normally distributed with a mean of 22 oz and a standard deviation of 0.5 oz. What is the probability that a loaf is larger than 21 oz? Round your answer to four places after the decimal.

Question 29

- The local operations manager for the IRS must decide whether to hire 1, 2, or 3 temporary workers. He estimates that net revenues will vary with how well taxpayers comply with the new tax code.
If he thinks the chances of low, medium, and high compliance are 20%, 30%, and 50% respectively, what is the expected value of perfect information? Round your answer to the nearest dollar.

Question 30

- The local operations manager for the IRS must decide whether to hire 1, 2, or 3 temporary workers. He estimates that net revenues will vary with how well taxpayers comply with the new tax code.
If he is conservative, how many new workers will he hire?

Question 31

1. Given the following random number ranges and the following random number sequence: 62, 13, 25, 40, 86, 93, determine the average demand for the following distribution of demand.

Question 32

- Daily highs in Sacramento for the past week (from least to most recent) were: 95, 102, 101, 96, 95, 90 and 92. Develop a forecast for today using a 2 day moving average.

Question 33

- Consider the following annual sales data for 2001-2008.
Calculate the correlation coefficient . Use four significant digits after the decimal.

Question 34

- Daily highs in Sacramento for the past week (from least to most recent) were: 95, 102, 101, 96, 95, 90 and 92. Develop a forecast for today using a weighted moving average, with weights of .6, .3 and .1, where the highest weights are applied to the most recent data.

Question 35

1. Given the following data, compute the MAD for the forecast.

Question 36

- Given the following data on the number of pints of ice cream sold at a local ice cream store for a 6-period time frame:
Compute a 3-period moving average for period 4. Use two places after the decimal.

Question 37

- The following data summarizes the historical demand for a product.
Use exponential smoothing with α = .2 and the smoothed forecast for July is 32. Determine the smoothed forecast for August.

Question 38

- The following sales data are available for 2003-2008.
Determine a 4-year weighted moving average forecast for 2009, where weights are W1 = 0.1, W2 = 0.2, W3 = 0.2 and W4 = 0.5.

Question 39

- Robert wants to know if there is a relation between money spent on gambling and winnings.
What is the coefficient of determination? Use two significant places after the decimal.

Question 40

- The following sales data are available for 2003-2008 :
Calculate the absolute value of the average error. Use three significant digits after the decimal.

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**Category**: Essay Topics