Main page: https://www.rdocumentation.org/packages/datasets/versions/3.6.2/topics/WWWusage
WWWusage
## Time Series:
## Start = 1
## End = 100
## Frequency = 1
## [1] 88 84 85 85 84 85 83 85 88 89 91 99 104 112 126 138 146 151
## [19] 150 148 147 149 143 132 131 139 147 150 148 145 140 134 131 131 129 126
## [37] 126 132 137 140 142 150 159 167 170 171 172 172 174 175 172 172 174 174
## [55] 169 165 156 142 131 121 112 104 102 99 99 95 88 84 84 87 89 88
## [73] 85 86 89 91 91 94 101 110 121 135 145 149 156 165 171 175 177 182
## [91] 193 204 208 210 215 222 228 226 222 220
require(graphics)
work <- diff(WWWusage)
par(mfrow = c(2, 1)); plot(WWWusage); plot(work)
require(stats)
aics <- matrix(, 6, 6, dimnames = list(p = 0:5, q = 0:5))
for(q in 1:5) aics[1, 1+q] <- arima(WWWusage, c(0, 1, q),
optim.control = list(maxit = 500))$aic
for(p in 1:5)
for(q in 0:5) aics[1+p, 1+q] <- arima(WWWusage, c(p, 1, q),
optim.control = list(maxit = 500))$aic
## Warning in log(s2): NaNs produced
## Warning in log(s2): NaNs produced
round(aics - min(aics, na.rm = TRUE), 2)
## q
## p 0 1 2 3 4 5
## 0 NA 38.67 8.74 9.13 8.24 7.72
## 1 18.10 3.16 5.11 3.44 3.96 5.14
## 2 11.04 5.15 6.22 4.63 2.10 6.95
## 3 0.85 2.80 4.48 3.27 3.62 5.29
## 4 2.79 4.82 5.04 7.94 4.26 6.99
## 5 4.72 6.50 2.40 10.50 0.00 1.63