This is a data set modified from Mazerolle and Desrochers (2005) on the mass lost by frogs after spending two hours on one of three substrates that are encountered in some landscape types.
data(dry.frog)
A data frame with 121 observations on the following 16 variables.
Individual
a numeric identifier unique to each individual.
Species
a factor with levels Racla
.
Shade
a numeric vector, either 1 (shade) or 0 (no shade).
SVL
the snout-vent length of the individual.
Substrate
the substrate type, a factor with levels
PEAT
, SOIL
, and SPHAGNUM
.
Initial_mass
the initial mass of individuals.
Mass_lost
the mass lost in g.
Airtemp
the air temperature in degrees C.
Wind_cat
the wind intensity, either 0 (no wind), 1 (low wind), 2 (moderate wind), or 3 (strong wind).
Cloud
cloud cover expressed as a percentage.
cent_Initial_mass
centered inital mass.
Initial_mass2
initial mass squared.
cent_Air
centered air temperature.
Perc.cloud
proportion of cloud cover
Wind
wind intensity, either 1 (no or low wind) or 1 (moderate to strong wind).
log_Mass_lost
log of mass lost.
Note that the original analysis in Mazerolle and Desrochers (2005) consisted of generalized estimating equations for three mass measurements: mass at time 0, 1 hour, and 2 hours following exposure on the substrate.
# NOT RUN {
data(dry.frog)
## maybe str(dry.frog) ; plot(dry.frog) ...
# }
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