1A. Write expressions for the following models: AR(3) MA(4) ARMA(1, 2) 1B. For predicting whether the agricultural epide

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1a Write Expressions For The Following Models Ar 3 Ma 4 Arma 1 2 1b For Predicting Whether The Agricultural Epide 1 (40.34 KiB) Viewed 13 times

1A. Write expressions for the following models: AR(3) MA(4) ARMA(1, 2) 1B. For predicting whether the agricultural epidemic of powdery mildew in mango will erupt in a certain year in the state of Utar Pradesh in India, Misra et al. (2004) used annual outbreak records during 1987- 2000. The epidemic typically occurs in the third and fourth week of March in a given year. The authors used a logistic regression model with two weather predictors (maximum temperature and relative humidity to forecast an outbreak. The data are shown in the table below: Year 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 2000 Outbreak? Yes No No ARIMA(2, 1, 2) Yes No Yes No Yes No Yes No No Max temperature 30.14 30.66 26.31 28.43 29.57 31.25 30.35 30.71 30.71 33.07 31.50 29.50 Relative humidity 82.86 79.57 89.14 91.00 80.57 67.82 61.76 81.14 61.57 59.76 68.29 79.14 a) Write an equation for the model fitted by the researchers. Use predictor names instead of x notation. b) Create scatter plots of the two predictors, using different hues for epidemic and non-epidemic markers. Does there appear to be a relationship between epidemic status and the two predictors? c) Partition the data into training and validation periods, so that years 1987-1994 are the training period. Fit a logistic regression to the training period using the two predictors.