The addition model of classical time series;
Because the addition model in the classical time series (step 1-4 is the same as the multiplication model, so write from the fifth step).
The addition model of classical time series (step 1-4 is the same as the multiplication model, so it is written from step 5).
Step 5: Trend change
Because it is an additive model, the formula for excluding seasonal changes is (round (Sales-Seasonal Index, 2)).
Step 5: Trend change
Because it is an additive model, the result is a calculation formula after removing seasonal factors: (round(sales-seasonal index, 2).
Step 6:
By drawing a value excluding seasonality, the optimal clutch line is (Tt=0.594X+2 1.884).
Step 6:
Draw a picture with the value after removing the seasonal factor, and get the best clutch line as (Tt=0.594X+2 1.884).
Step 7: Forecast
Step 7: Forecast
Forecast data for the fourth year:
Using the data of the fourth year to forecast:
Calculate Tt by introducing the optimal clutch line obtained in the sixth step, and use the formula (Ft=round(Tt*St, 2)) to calculate Ft.
Calculate the value of (Tt) by using the optimal clutch line calculated after step 6, and calculate the value of (Ft) by using the formula (Ft=round(Tt*St, 2)).
Step 8: (Draw the predicted sales volume and actual sales volume in the fourth year)
By comparing the actual sales line and the forecast sales line in the fourth year, it is close.
Step 8: (Draw a chart of the predicted sales volume and actual sales volume in the fourth year)
By comparing the actual sales volume line and the predicted sales volume line in the fourth year, they are actually quite close.
Step 9:
The values of MAE and MSE are calculated by the formulas round ((ft-at)/12,2) and round ((ft-at) 2/12,2).
Step 9:
Use formulas ((ft-at)/12,2) and round ((ft-at) 2/12,2 to calculate the values of MAE and MSE.
Step 10:
Use the formula (= round ((ft-at) 2/ft, 2) to calculate the value of (ft-at) 2/ft. When the degree of freedom is 1 1 and the significance level is 5%, the chi-square value is 19.68.
Step 10:
Use the formula (= round ((ft-at) 2/ft, 2) to calculate the value of (ft-at) 2/ft.) When the degree of freedom is 1 1, the significance level is 5% and the chi-square value is 19.68.