GM: Grey Model Fitting

In GreyModel: Fitting and Forecasting of Grey Model

Description

The GM function fit GM (1, 1) model for time series data.

Usage

GM(data)

Arguments

data	Input univariate time series (ts) data.

Details

In situations where there are limited observations available for modelling, grey modelling may be employed (Hsu and Wang, 2007). Using the OLS approach, this function calculates the parameters (a and b) of the GM (1, 1) model. Additionally, this function returns the model's fitted values and different evaluation criteria.

Value

a	Grey model parameter
b	Grey model parameter
MAE_Grey	Mean Absolute Error (MAE) of fitted Grey model
MAPE_Grey	Mean Absolute Percentage Error (MAPE) of fitted Grey model
MSE_Grey	Mean Square Error (MSE) of fitted Grey model
RMSE_Grey	Root Mean Square Error (RMSE) of fitted Grey model
fitted	Fitted values of Grey model

References

Hsu, L. and Wang, C. (2007). Forecasting the output of integrated circuit industry using a grey model improved by the Bayesian analysis. Technological Forecasting and Social Change, 74, 843–853.

Mao, M. and Chirwa, E. C. (2006). Application of grey model GM(1, 1) to vehicle fatality risk estimation. Technological Forecasting and Social Change, 73, 588–605.

See Also

GM_test, fcast_grey

Examples

xt <- c(640,724,813,1145,1509,2122,1883,2413,2834,4235,7144,5269)
GM(xt)

GreyModel documentation built on Sept. 13, 2021, 5:06 p.m.