I do not know if you use Excel or SPSS statistical package but this problem can be solved easily on SPSS.
let me know.
I need some help with figuring out the ratio-to-moving average. Can someone help me?
Here's the problem:
Sales of roof material, by quarter, since 1994 for Carolina Home Construction, Inc. are shown below (in $000):
Quarter
Year I II III IV
1994 210 180 60 246
1995 214 216 82 230
1996 246 228 91 280
1997 258 280 113 298
1998 279 267 116 304
1999 302 290 114 310
2000 321 291 120 320
a. Determine the typical seasonal patterns for sales using the ratio-to-moving average method.
b. Deseasonalize the data and determine the trend equation.
c. Project the sales for 2001, and then seasonally adjust each quarter.
4 answers
You can look for this chapter .. google it and on page 40 there is a similar example solved using excel
Chapter 16 - Time Series and Forecasting - McGraw-Hill
Chapter 16 - Time Series and Forecasting - McGraw-Hill
even better..
here is an example on youtube
Excel - Time Series Forecasting - Part 1 of 3
here is an example on youtube
Excel - Time Series Forecasting - Part 1 of 3
Ok solving this problem using Excel and 4-year moving average, here are the answers:
a. the seasonality components are as follows: Q1=1.18, Q2=1.14, Q3=0.43, and Q4=1.24
b. the trend equation is Sales = 164.69 (intercepT) + 4.14 (slope) * Time Period
where time period is the quarter. For year 2 quarter 3, the time period would be 7
c. The forecast for year 2001 seasonally adjusted sales is as follows:
Q1= 337.3, Q2=328.5, Q3=126.7 and Q4 369.9
Good luck.
Hussein.elsayed at gmail
a. the seasonality components are as follows: Q1=1.18, Q2=1.14, Q3=0.43, and Q4=1.24
b. the trend equation is Sales = 164.69 (intercepT) + 4.14 (slope) * Time Period
where time period is the quarter. For year 2 quarter 3, the time period would be 7
c. The forecast for year 2001 seasonally adjusted sales is as follows:
Q1= 337.3, Q2=328.5, Q3=126.7 and Q4 369.9
Good luck.
Hussein.elsayed at gmail
1 answer