# Forecasting Calulations

**PRODUCTION MANAGEMENT:**

**ASSIGNMENT # 5 FORECASTING**

STUDENT’S NAME_____________________________________________

**!!!!!!!!! NOTE: YOU MUST TYPE YOUR WORK!!!!!!!!!!!!!!**

**NOTE! IN ALL CASES, SOLVE YOUR PROBLEMS AND CREAT THE TABLE USING THE VALUES OR FIGURES FROM YOUR CALCULATIONS. IN ADDITION, YOUR TABLES MUST HAVE THE APPROPRIATE HEADINGS THAT IS BEING CALCULATED**.

*NOTE! Without submitting the separate calculations of the forecast, you will not earn points if you only insert the figures in the forecast column of the table.*

**Table 1.**The manager of Carpet City outlet store needs to be able to forecast accurately demand for Soft Shang carpet. Demand for the past 20 weeks appears in table 1 below.

week | Demand | Forecast | Error | ABS. Dev | Squared Error | APE |

1 | 20 | |||||

2 | 28 | |||||

3 | 22 | |||||

4 | 18 | |||||

5 | 22 | |||||

6 | 22 | |||||

7 | 22 | |||||

8 | 26 | |||||

9 | 23 | |||||

10 | 23 | |||||

11 | 23 | |||||

12 | 27 | |||||

13 | 25 | |||||

14 | 22 | |||||

15 | 23 | |||||

16 | 14 | |||||

17 | 14 | |||||

18 | 15 | |||||

19 | 11 | |||||

20 | 16 | |||||

21 | ||||||

22 | ||||||

23 | ||||||

24 | ||||||

**Table 1.**

**Create a five-week moving average and compute the followings:**

a). The mean absolute deviation (MAD)_____________________________

b.)The mean squared error (MSE)__________________________________

c). The mean absolute percentage error (MAPE)_______________________

**Table 2. **The manager of Carpet City outlet store needs to be able to forecast accurately demand for Soft Shang carpet. Demand for the past 20 weeks appears in table 1 below

week | Demand | Forecast | Error | Abs.Dev | SQ Error | APE |

1 | 20 | |||||

2 | 28 | |||||

3 | 22 | |||||

4 | 18 | |||||

5 | 22 | |||||

6 | 22 | |||||

7 | 22 | |||||

8 | 26 | |||||

9 | 23 | |||||

10 | 23 | |||||

11 | 23 | |||||

12 | 27 | |||||

13 | 25 | |||||

14 | 22 | |||||

15 | 23 | |||||

16 | 14 | |||||

17 | 14 | |||||

18 | 15 | |||||

19 | 11 | |||||

20 | 16 | |||||

21 | ||||||

22 | ||||||

23 | ||||||

24 | ||||||

Using the exponential smoothing forecasting techniques with α = .40.

a). Compute the exponentially smoothed forecast average without trend**: Use this formula Ft = α(At-1) +(1- α) Ft-1 **to calculate separately the forecast for all the required weeks in the table provided, before inserting the answers from your calculations in the forecast column of the table.

b). Calculate the Mean Absolute Deviation (MAD). ________________

c). Mean Square Error (MSE). _________________________________

d). Mean Absolute Percentage Error (MAPE). _____________________

**TABLE:3**

Period | Demand | forecast | Weighted
Moving average forecast |
Exponential
Smoothing forecast |
X2 | xy |

1 | 1600 | |||||

2 | 2200 | |||||

3 | 2000 | |||||

4 | 1600 | |||||

5 | 2500 | |||||

6 | 3500 | |||||

7 | 3300 | |||||

8 | 3200 | |||||

9 | 3900 | |||||

10 | 4700 | |||||

11 | 4300 | |||||

12 | 4400 | |||||

13 | ||||||

a. . Calculate the forecast for the data using a four-year moving average.

b. Use the data to calculate the forecast for period 5 using a four-period weighted average moving average. The weights of .4, .3, .2, and .1 are assigned to the most recent, second most recent, third most recent and the fourth most recent respectively.

c. Based on the data, calculate the forecast from period three using the **exponential smoothing method**. Assume the forecast for period two is 1600 and

d. Use the data to estimate the linear trend forecast using the simple linear regression to

calculate the trend line and the forecast for period 13 **OR estimate the regression equation for period 13. NOTE!!! In this question, you are required to show all your calculations for each of the trend lines to enable you estimate or forecast the demand for period 13.**

1

6