Dear All
I've fitted a GAMM to relate water temperature to the day of the year (DOY) at
three different sites. I used summary(MFinal$gam) and anova(MFinal$gam) to
produce the output of my model. I'm confused on how to report the degrees of
freedom for the smother and the factor. I currently have
"The final model suggested water temperature was significant related to DOY
(6.46 estimated degrees of freedom, F = 224.2, p < 0.001) and was significantly
different between sites (F2 = 82.14, p <0.001)"
But think there should be more to the degrees of freedom particularly for the
sites factor.
If anyone could advise on the correct way to display the results I would
greatly appreciate it . The output from the model is below
Best wishes
Tom
> summary(MFinal$gam)
Family: gaussian
Link function: identity
Formula:
Temperature ~ s(DOY) + Site
Parametric coefficients:
Estimate Std. Error t value Pr(>|t|)
(Intercept) 12.0366 0.2411 49.92 <2e-16 ***
SiteG 4.2460 0.3979 10.67 <2e-16 ***
SiteH 4.1439 0.4069 10.19 <2e-16 ***
---
Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
Approximate significance of smooth terms:
edf Ref.df F p-value
s(DOY) 6.457 6.457 224.2 <2e-16 ***
---
Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
R-sq.(adj) = 0.914 Scale est. = 0.098602 n = 137
> anova(MFinal$gam)
Family: gaussian
Link function: identity
Formula:
Temperature ~ s(DOY) + Site
Parametric Terms:
df F p-value
Site 2 82.14 <2e-16
Approximate significance of smooth terms:
edf Ref.df F p-value
s(DOY) 6.457 6.457 224.2 <2e-16
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