My aim was to perform a a generalized additive model with penalized splines to
analyze the relationship between daily mortality and PM10 levels, and to
control for the non-linear confounding effects of weather (temperature =
Tmax; humidity = umidità).
this is my complete analysis:
> x.gam <- gam(mortality ~ s(PM10) + (Tmax) + (umidità), data = sab, family =
> quasipoisson)
> summary (x.gam)
Family: quasipoisson
Link function: log
Formula:
mortality ~ s(PM10) + (Tmax) + (umidità)
Parametric coefficients:
Estimate Std. Error t value Pr(>|t|)
(Intercept) 1.50456 0.83802 1.795 0.0784 .
Tmax 0.02060 0.01760 1.170 0.2472
umidità 0.01256 0.00826 1.520 0.1345
---
Signif. codes: 0 *** 0.001 ** 0.01 * 0.05 . 0.1 1
Approximate significance of smooth terms:
edf Ref.df F p-value
s(PM10) 3.067 3.857 4.862 0.00235 **
---
Signif. codes: 0 *** 0.001 ** 0.01 * 0.05 . 0.1 1
R-sq.(adj) = 0.269 Deviance explained = 34.2%
GCV score = 6.6782 Scale est. = 5.9797 n = 58
Can I assume that the y axis of the plot (which is labeled "sPM10,3.07)
plot(x.gam, page =1)
is the log relative risk ?
thanks again
agostino
Il giorno 02/lug/2014, alle ore 16:41, David Winsemius <[email protected]>
ha scritto:
>
> On Jul 2, 2014, at 1:25 AM, [email protected] wrote:
>
>> Sorry for my unclear request and description
>> I performed:
>>
>> x.gam <- gam(mortality ~ s(PM10) + (Tmax) + (umidity), data = data, family =
>> quasipoisson)
>> plot(x.gam, page =1)
>>
>> the plot showed on the left axis "sPM10,3.07".
>> How can I have "Log relative risk" ?
>
> You just want to change the axis label? Then add this to the plot call:
>
> ylab="Log Relative Hazard"
>
> Again, you have not told us anything about the data, so we remain unable to
> say whether the results corresponds to that label change, but with a
> quasipoisson link one might expect a logged estimate of <something>.
>
> --
> David
>
>> thanks again for your kind help
>> agostino
>>
>> Il 02.07.2014 08:42 David Winsemius ha scritto:
>>
>>> On Jul 1, 2014, at 11:33 PM, [email protected]:
>>>> Dear David, many thanks for your reply. The aim was to evaluate the
>>>> relationship between daily mortality (variable "mortality") and mean daily
>>>> values of PM10 levels (variable "PM10") in a specific geographic area,
>>>> considering the effect of meteorological confounders (temperature,
>>>> umidity). I used the following model (mgcv package): gam(mortality ~
>>>> (PM10) + (Tmax) + (umidity), data = data, family = quasipoisson) the
>>>> question is: how can I obtain a plot of log-relative risk of daily
>>>> mortality vs. PM10 levels? regards
>>> Still rather unclear what the problem is. I see no error message in your
>>> question. Are you asking how to assign a model to a name and then call the
>>> plot method?
>>>
>>> mdlAgostino
>>> Il 02.07.2014 01:50 David Winsemius ha scritto:
>>>
>>>> On Jul 1, 2014, at 12:02 AM, adc wrote:
>>>>> I performed the following GAM by the MGCV package:
>>>> I think it's actually spelled in all lower case.
>>>>> gam(mortality ~ (PM10) + (Tmax) + (umidity), data = data, family =
>>>>> quasipoisson) How can I obtain a plot of Log-relative risk of mortality
>>>>> vs. PM10 ? thanks
>>>> Shouldn't we need to know more details about the experimental setup to
>>>> answer that question? And what sort of comparisons you are requesting? And
>>>> about what parts of ?mgcv::plot.gam you need further explanations to
>>>> answer the question?
>>>>> agostino
>>>> snipped
>>>>> --
>>>> snipped
>>>>> Sent from the R help mailing list archive at Nabble.com. [[alternative
>>>>> HTML version deleted]]
>>>> snipped
>>>>> PLEASE do read the posting guide
>>>>> http://www.R-project.org/posting-guide.html and provide commented,
>>>>> minimal, self-contained, reproducible code.
>>>> David Winsemius Alameda, CA, USA
>>>> ______________________________________________ [email protected]
>>>> mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read
>>>> the posting guide http://www.R-project.org/posting-guide.html and provide
>>>> commented, minimal, self-contained, reproducible code.
>>>
>>> Scopri istella, il nuovo motore per il web italiano.
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>>>
>>>
>> David Winsemius Alameda, CA, USA
>>
>>
>>
>> Scopri istella, il nuovo motore per il web italiano.
>> Istella garantisce risultati di qualità e la possibilità di condividere, in
>> modo semplice e veloce, documenti, immagini, audio e video.
>> Usa istella, vai su http://www.istella.it?wtk=amc138614816829636
>>
>
> David Winsemius
> Alameda, CA, USA
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