colifCount: Coliform counts in sea-water samples
Description
Transformed counts of faecal coliform bacteria in sea water
samples collected at seven locations near Sydney NSW, Australia.
There were four controls: Longreef, Bondi East, Port
Hacking 50, and Port Hacking 100 and three
outfalls: Bondi Offshore, Malabar Offshore and North
Head Offshore. At each location measurements were made at four
depths: 0, 20, 40, and 60 meters. A large fraction of the counts
are missing values.source
The data were kindly supplied by Geoff Coade, of the New South
Wales Environment Protection Authority (Australia)Modelling
The hidden Markov models applied to these data by Turner et
al. (1998) and by Turner (2008) were much more complex and
elaborate than those fitted in the examples in this package.
See the references for details.Details
The observations corresponding to each location-depth combination
constitute a time series. The sampling interval is ostensibly
1 week; distinct time series are ostensibly synchronous.
The measurements were made over a 194 week period. Due to
exigencies of weather, the unreliabitity of boats and other
factors the collection times were actually highly irregular
and have been rounded to the neares week. Often no sample was
obtained at a given site within a week of the putative collection
time, in which the observed count is given as a missing value. In
fact over 75% of the counts are missing. See Turner et
al. (1998) for more detail.References
T. Rolf Turner, Murray A. Cameron, and Peter J. Thomson. Hidden
Markov chains in generalized linear models. Canadian J. Statist.
26 (1998) 107 -- 125.
Rolf Turner. Direct maximization of the likelihood of a hidden
Markov model. Comp. Statist. Data Anal. 52 (2008)
4147--4160.