Extremely high and low values in some iterations using iBoot

[ferowland]

I am currently rerunning a model that looks at a 10 yr moving window with nBoot = 200, and I keep noticing odd iteration values. Here is some output from 1998-2007:

iBoot, xConc and xFlux 127 -8.615097e+137 -2.975343e+136
iBoot, xConc and xFlux 128 -0.05028564 -1.459841
iBoot, xConc and xFlux 129 0.03666643 -0.1706541
iBoot, xConc and xFlux 130 0.05564319 0.03039397
iBoot, xConc and xFlux 131 0.04101899 -0.1198773
iBoot, xConc and xFlux 132 0.04211883 0.1540202
iBoot, xConc and xFlux 133 -0.09984916 -2.680429
iBoot, xConc and xFlux 134 -0.007287396 -0.3895768
iBoot, xConc and xFlux 135 0.002760677 -0.7174396
iBoot, xConc and xFlux 136 -0.001037794 -0.5118047
iBoot, xConc and xFlux 137 0.0370652 -0.2164727
iBoot, xConc and xFlux 138 -0.02083882 -0.5030731
iBoot, xConc and xFlux 139 0.02780439 -0.294982
iBoot, xConc and xFlux 140 0.003192806 -0.4554299
iBoot, xConc and xFlux 141 -0.05443917 -1.415746
iBoot, xConc and xFlux 142 0.03259536 -0.466467
iBoot, xConc and xFlux 143 0.01166099 -0.1782373
iBoot, xConc and xFlux 144 0.03090554 -0.2704868
iBoot, xConc and xFlux 145 -0.01288284 -1.037976
iBoot, xConc and xFlux 146 0.1241648 0.8563349
iBoot, xConc and xFlux 147 -0.03576329 -1.28158
iBoot, xConc and xFlux 148 2.897706e+30 1.57178e+32
iBoot, xConc and xFlux 149 0.08204259 0.3758117
iBoot, xConc and xFlux 150 -0.01351132 -0.4975678
iBoot, xConc and xFlux 151 0.01373099 -0.1204261
iBoot, xConc and xFlux 152 0.0691038 0.1389613
iBoot, xConc and xFlux 153 0.009624788 -0.4152171
iBoot, xConc and xFlux 154 -0.06310256 -1.229834
iBoot, xConc and xFlux 155 -0.03640907 -1.312824
iBoot, xConc and xFlux 156 0.02100833 -0.2485315
iBoot, xConc and xFlux 157 0.01610422 -0.3146633
iBoot, xConc and xFlux 158 -0.01941998 -1.072092
iBoot, xConc and xFlux 159 -0.06849002 -1.519826
iBoot, xConc and xFlux 160 0.06798843 0.2361849
iBoot, xConc and xFlux 161 0.01927036 -0.3341333
iBoot, xConc and xFlux 162 0.005404621 -0.6666091
iBoot, xConc and xFlux 163 0.04532531 -0.4035346
iBoot, xConc and xFlux 164 0.1073366 0.2855145
iBoot, xConc and xFlux 165 -0.02089126 -1.265881
iBoot, xConc and xFlux 166 -0.03983874 -1.183583
iBoot, xConc and xFlux 167 -1.307639e+79 -4.516112e+77
iBoot, xConc and xFlux 168 0.02232687 -0.2135413
iBoot, xConc and xFlux 169 -0.02690708 -1.169837
iBoot, xConc and xFlux 170 0.05313271 0.02626181
iBoot, xConc and xFlux 171 0.06698775 0.1982021
iBoot, xConc and xFlux 172 0.03341398 -0.7828989
iBoot, xConc and xFlux 173 0.07338573 0.1200608
iBoot, xConc and xFlux 174 0.07082601 0.122985
iBoot, xConc and xFlux 175 -7.434473e+101 -2.567598e+100
iBoot, xConc and xFlux 176 0.07073133 0.1410189
iBoot, xConc and xFlux 177 0.01842965 -0.3556271
iBoot, xConc and xFlux 178 -0.09302633 -2.252569
iBoot, xConc and xFlux 179 0.07934037 0.3939216
iBoot, xConc and xFlux 180 0.01684882 -0.2692689
iBoot, xConc and xFlux 181 0.02964044 -0.3813411
iBoot, xConc and xFlux 182 0.004074809 -0.3463523
iBoot, xConc and xFlux 183 -0.05169548 -1.534628
iBoot, xConc and xFlux 184 0.03390354 -0.1392435
iBoot, xConc and xFlux 185 0.06523865 0.07551456
iBoot, xConc and xFlux 186 0.0444889 -0.09759831
iBoot, xConc and xFlux 187 0.006336869 -0.4673323
iBoot, xConc and xFlux 188 -0.02044203 -1.04437
iBoot, xConc and xFlux 189 0.03901774 0.08431938
iBoot, xConc and xFlux 190 -0.04834053 -1.364399
iBoot, xConc and xFlux 191 -0.05268685 -1.252619
iBoot, xConc and xFlux 192 0.07842773 0.221899
iBoot, xConc and xFlux 193 -0.02316459 -1.329317
iBoot, xConc and xFlux 194 -0.09582452 -1.921
iBoot, xConc and xFlux 195 0.1049984 0.6393139
iBoot, xConc and xFlux 196 0.02325422 -0.2404297
iBoot, xConc and xFlux 197 -0.06165737 -1.684607
iBoot, xConc and xFlux 198 0.0514432 -0.08819077
iBoot, xConc and xFlux 199 -0.04280059 -1.591571
iBoot, xConc and xFlux 200 0.004167874 -0.5705411

It took 203 iterations to achieve 200 sucessful runs.

Maumee River at Waterville OH
TKN through 2007
Water Year

Change estimates are for 2007 minus 1998

Should we reject Ho that Flow Normalized Concentration Trend = 0 ? Do Not Reject Ho
best estimate of change in concentration is 0.0194 mg/L
Lower and Upper 90% CIs -1.19e-01 7.84e-02
also 95% CIs -1.46e+101 1.04e-01
and 50% CIs -2.75e-02 3.97e-02
approximate two-sided p-value for Conc 0.82
Likelihood that Flow Normalized Concentration is trending up = 0.59 is trending down = 0.41

Should we reject Ho that Flow Normalized Flux Trend = 0 ? Do Not Reject Ho
best estimate of change in flux is -0.409 10^6 kg/year
Lower and Upper 90% CIs -2.66e+00 2.80e-01
also 95% CIs -5.04e+99 4.97e-01
and 50% CIs -1.13e+00 -1.22e-01
approximate two-sided p-value for Flux 0.36
Likelihood that Flow Normalized Flux is trending up = 0.177 is trending down = 0.823

Do you have any idea why some of the iterations are so off? Thank you!

[ldecicco-USGS]

Wow! I have not seen that before. Is there anything unusual about the data? Maybe a bunch of right-censored values or something? Can you paste in here the result of:

plot(eList)

[ferowland]

Thank you for your lightning fast response. Here is the plot: