STEVENSON OPERATIONS MANAGEMENT W/CONNEC
14th Edition
ISBN: 9781264578306
Author: Stevenson
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Textbook Question
Chapter 3, Problem 4DRQ
a. Why are forecasts generally wrong?
b. Explain the term “wrong” as it pertains to a good forecast.
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Students have asked these similar questions
a) Apply moving average and exponential smoothing to generate two forecasts of the closing price for the entire data period. Set appropriate values for the forecast parameters (e.g., k and a).
b) Plot and compare the actual and predicted data values you calculated in part (b). Provide one chart that displays actual, moving average, and exponential smoothing lines. Hint: Calculate MSE, MAD, or MAPE to compare the different forecasts.
Develop your own forecast from scratch. Do NOT use Excel’s Data Analysis or Forecast Sheets.
eBook
Problem 6-05
Consider the following time series data.
3
16
Week 1
Week
2
Value 18 13
a. Choose the correct time series plot
(1)
€
(!!!)
Time Series Value
Time Series Value
28642986420
284H2G86420
1
4
11
2
{B}
2
TH
3
Week (t)
Week (t)
5
6
€
(iv)
Time Series Value
Time Series Value
28642 NO
28642 NO
1
2
2
4
3₁
Week (t)
Week (t)
5
6
Two independent methods of forecasting based on judgment and experience have been prepared each month for the past 10 months. The forecasts and actual sales are in the attached screenshot. Required: Compute the MAD and MSE for each forecast. Does either forecast seem superior? Explain.
Chapter 3 Solutions
STEVENSON OPERATIONS MANAGEMENT W/CONNEC
Ch. 3.15 - Prob. 1.1RQCh. 3.15 - Prob. 1.2RQCh. 3.15 - Prob. 1.3RQCh. 3 - What are the main advantage that quantitative...Ch. 3 - What are some of the consequences of poor...Ch. 3 - List the specific weaknesses of each of these...Ch. 3 - Forecasts are generally wrong a. Why are forecasts...Ch. 3 - What is the purpose of establishing control limits...Ch. 3 - What factors would you consider in deciding...Ch. 3 - Contrast the use of MAD and MSE in evaluating...
Ch. 3 - What advantages as a forecasting tool does...Ch. 3 - How does the number of periods in a moving average...Ch. 3 - What factors enter into the choice of a value for...Ch. 3 - Prob. 11DRQCh. 3 - Explain how using a centered moving average with a...Ch. 3 - Contrast the terms sales and demand.Ch. 3 - Contrast the reactive and proactive approaches to...Ch. 3 - Explain how flexibility in production systems...Ch. 3 - How is forecasting in the context of a supply...Ch. 3 - Which type of forecasting approach, qualitative or...Ch. 3 - Prob. 18DRQCh. 3 - Choose the type of forecasting technique (survey,...Ch. 3 - Explain the trade-off between responsiveness and...Ch. 3 - Who needs to be involved in preparing forecasts?Ch. 3 - How has technology had an impact on forecasting?Ch. 3 - It has been said that forecasting using...Ch. 3 - What capability would an organization have to have...Ch. 3 - When a new business is started, or a patent idea...Ch. 3 - Discuss how you would manage a poor forecast.Ch. 3 - Omar has beard from some of his customers that...Ch. 3 - Give three examples of unethical conduct involving...Ch. 3 - A commercial baker, has recorded sales (in dozens)...Ch. 3 - National Scan, Inc., sells radio frequency...Ch. 3 - A dry cleaner uses exponential smoothing to...Ch. 3 - An electrical contractors records during the last...Ch. 3 - A cosmetics manufacturers marketing department has...Ch. 3 - Prob. 6PCh. 3 - Freight car loadings ova a 12-year period at a...Ch. 3 - Air travel on Mountain Airline for the past 18...Ch. 3 - a. Obtain the linear trend equation for the...Ch. 3 - After plotting demand for four periods, an...Ch. 3 - A manager of a store that sells and installs spas...Ch. 3 - The following equation summarizes the trend...Ch. 3 - Compute seasonal relatives for this data the SA...Ch. 3 - A tourist center is open on weekends (Friday,...Ch. 3 - The manager of a fashionable restaurant open...Ch. 3 - Obtain estimates of daily relatives for the number...Ch. 3 - A pharmacist has been monitoring sales of 2...Ch. 3 - New car sales for a dealer in Cook County,...Ch. 3 - The following table shows a tool and die companys...Ch. 3 - An analyst must decide between two different...Ch. 3 - Two different forecasting techniques (F1 and F2)...Ch. 3 - Two independent methods of forecasting based on...Ch. 3 - Long-Life Insurance has developed a linear model...Ch. 3 - Timely Transport provides local delivery service...Ch. 3 - The manager of a seafood restaurant was asked to...Ch. 3 - The following data were collected during a study...Ch. 3 - Lovely Lawns Inc., intends to use sales of lawn...Ch. 3 - The manager of a travel agency has been using a...Ch. 3 - Refer to the data in problem 22 a. Compute a...Ch. 3 - The classified department of a monthly magazine...Ch. 3 - A textbook publishing company has compiled data on...Ch. 3 - A manager has just receded an valuation from an...Ch. 3 - A manager uses this equation to predict demand for...Ch. 3 - A manager uses a trend equation plus quarterly...Ch. 3 - ML MANUFACTURING ML Manufacturing makes various...Ch. 3 - ML MANUFACTURING ML Manufacturing makes various...Ch. 3 - HIGHLINE FINANCIAL SERVICES, LTD. Highline...
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- The owner of a restaurant in Bloomington, Indiana, has recorded sales data for the past 19 years. He has also recorded data on potentially relevant variables. The data are listed in the file P13_17.xlsx. a. Estimate a simple regression equation involving annual sales (the dependent variable) and the size of the population residing within 10 miles of the restaurant (the explanatory variable). Interpret R-square for this regression. b. Add another explanatory variableannual advertising expendituresto the regression equation in part a. Estimate and interpret this expanded equation. How does the R-square value for this multiple regression equation compare to that of the simple regression equation estimated in part a? Explain any difference between the two R-square values. How can you use the adjusted R-squares for a comparison of the two equations? c. Add one more explanatory variable to the multiple regression equation estimated in part b. In particular, estimate and interpret the coefficients of a multiple regression equation that includes the previous years advertising expenditure. How does the inclusion of this third explanatory variable affect the R-square, compared to the corresponding values for the equation of part b? Explain any changes in this value. What does the adjusted R-square for the new equation tell you?arrow_forwardThe file P13_22.xlsx contains total monthly U.S. retail sales data. While holding out the final six months of observations for validation purposes, use the method of moving averages with a carefully chosen span to forecast U.S. retail sales in the next year. Comment on the performance of your model. What makes this time series more challenging to forecast?arrow_forwardThe file P13_29.xlsx contains monthly time series data for total U.S. retail sales of building materials (which includes retail sales of building materials, hardware and garden supply stores, and mobile home dealers). a. Is seasonality present in these data? If so, characterize the seasonality pattern. b. Use Winters method to forecast this series with smoothing constants = = 0.1 and = 0.3. Does the forecast series seem to track the seasonal pattern well? What are your forecasts for the next 12 months?arrow_forward
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