SOLVED MGMT717 Assignment 1 Solution and Discussion

ADVANCED PRODUCTION PLANNING & INVENTORY CONTROL (MGMT717)
ASSIGNMENT # 1
Due Date: November 27, 2019 Marks: 10 SCENARIO:
The supply chain manager of a manufacturing company is interested in finding the best method of forecasting for a special set of gears that enhances the speed of the car. He is
confused between “Weighted Moving Average” method and “Exponential Smoothing” method. The demand of the product is given in the following table:Month 1 2 3 4 5 6 7 8 9 10 11 12 13 Demand 60 55 43 65 52 42 47 59 63 44 55 49 ? QUESTIONS:
 Your task is to help the manager to arrive at a decision by forecasting the demands for all possible months through the following methods:
a. 3Period Weighted Moving Average with weights 0.5, 0.3 and 0.2 (the most recent period carries maximum weight). (4)
b. Exponential Smoothing with 𝛼 = 0.2 (4)  Calculate Mean Absolute Deviation (MAD) for both methods and conclude which forecasting model is more appropriate for the product. (2)
Instructions:
• Use the demand of the first month as the Forecast of the first month for the sake of calculations
• You have to calculate forecasts and present these in tables
• Write formulae and show necessary calculations
• You may solve the problem in MS Excel and copypaste tables in your solution file (MS
Word format)
• Watch video lectures and consult book to complete the assignment
Important:
24 hours extra / grace period after the due date are usually available to overcome uploading difficulties. This extra time should only be used to meet the emergencies and above mentioned due dates should always be treated as final to avoid any inconvenience.
Deadline:
• Make sure to upload the solution file before the due date on VULMS.
• Any submission made via email after the due date will not be accepted.
Formatting Guidelines:
• Use the font style “Times New Roman” or “Arial” and font size “12”.
• It is advised to compose your document in MSWord format.
• You may also compose your assignment in Open Office format.
• Use black and blue font colors only.
Referencing Guidelines:
• Use APA style for referencing and citation. For guidance search “APA reference style” in Google and read various websites containing information for better understanding or visit http://linguistics.byu.edu/faculty/henrichsenl/apa/APA01.html
Rules for Marking
Please note that your assignment will not be graded or graded as Zero (0), if:
• Any of the given instructions is not followed
• It is copied or plagiarized
• It is submitted after the due date.
• The file you uploaded does not open or is corrupt.  Your task is to help the manager to arrive at a decision by forecasting the demands for all possible months through the following methods:

Solution: 1.
a) Weighted Moving Average:Month Demand Forecast Error Error 1 60 2 55 3 43 4 65 50.0 15.0 15.0 5 52 56.4 4.4 4.4 6 42 54.1 12.1 12.1 7 47 49.6 2.6 2.6 8 59 46.5 12.5 12.5 9 63 52.0 11.0 11.0 10 44 58.6 14.6 14.6 11 55 52.7 2.3 2.3 12 49 53.3 4.3 4.3 13 ? 49.8 Total 78.8  Forecast for Period 4 = 430.5 + 550.3 + 60*0.2
 Forecast for Period 5 = 650.5 + 430.3 + 55*0.2
 Forecast for Period 13 = 490.5 + 550.3 + 44*0.2 = 49.8
b) Exponential Smoothing:
𝛼=0.2Month Demand Forecast Error Error Month Demand Forecast Error Error 1 60 60.00 2 55 60.00 5.00 5.00 3 43 59.00 16.00 16.00 4 65 55.0 9.20 9.20 5 52 55.8 5.64 5.64 6 42 57.64 14.51 14.51 7 47 56.51 6.61 6.61 8 59 53.61 6.71 6.71 9 63 53.63 9.37 9.37 10 44 55.50 11.50 11.50 11 55 53.2 1.80 1.80 12 49 53.56 4.56 4.56 13 ? 52.65 Total 90.90  Ft+1 =Ft +α(At –Ft) or Ft+1 =αAt +(1–α)Ft
 F1 = A1 (Supposed) = 60
 F2 =F1 +α(A1 –F1)=60+0.2(60–60)=60
 F3 =F2 +α(A2 –F2)=60+0.2(55–60)=59
 F13 =F12 +α(A12 –F12)=53.56+0.2(49–53.56)=52.65
 MAD
MAD = ∑ Actual Demand – Forecast / n
a) Weighted Moving Average:
 MAD=78.8/9=8.76
b) Exponential Smoothing:  MAD=90.90/11=8.26
As MAD of Exponential Smoothing is less than that of Weighted Moving Average, it is concluded that Exponential Smoothing is more appropriate.

Solution: 1.
a) Weighted Moving Average:Month Demand Forecast Error Error 1 60 2 55 3 43 4 65 50.0 15.0 15.0 5 52 56.4 4.4 4.4 6 42 54.1 12.1 12.1 7 47 49.6 2.6 2.6 8 59 46.5 12.5 12.5 9 63 52.0 11.0 11.0 10 44 58.6 14.6 14.6 11 55 52.7 2.3 2.3 12 49 53.3 4.3 4.3 13 ? 49.8 Total 78.8  Forecast for Period 4 = 430.5 + 550.3 + 60*0.2
 Forecast for Period 5 = 650.5 + 430.3 + 55*0.2
 Forecast for Period 13 = 490.5 + 550.3 + 44*0.2 = 49.8
b) Exponential Smoothing:
𝛼=0.2Month Demand Forecast Error Error Month Demand Forecast Error Error 1 60 60.00 2 55 60.00 5.00 5.00 3 43 59.00 16.00 16.00 4 65 55.0 9.20 9.20 5 52 55.8 5.64 5.64 6 42 57.64 14.51 14.51 7 47 56.51 6.61 6.61 8 59 53.61 6.71 6.71 9 63 53.63 9.37 9.37 10 44 55.50 11.50 11.50 11 55 53.2 1.80 1.80 12 49 53.56 4.56 4.56 13 ? 52.65 Total 90.90  Ft+1 =Ft +α(At –Ft) or Ft+1 =αAt +(1–α)Ft
 F1 = A1 (Supposed) = 60
 F2 =F1 +α(A1 –F1)=60+0.2(60–60)=60
 F3 =F2 +α(A2 –F2)=60+0.2(55–60)=59
 F13 =F12 +α(A12 –F12)=53.56+0.2(49–53.56)=52.65
 MAD
MAD = ∑ Actual Demand – Forecast / n
a) Weighted Moving Average:
 MAD=78.8/9=8.76
b) Exponential Smoothing:  MAD=90.90/11=8.26
As MAD of Exponential Smoothing is less than that of Weighted Moving Average, it is concluded that Exponential Smoothing is more appropriate.