[R] producing a graph with glm poisson distributed respons count data and categorical independant variables
babs
bas_pauwels at hotmail.com
Sat Jul 28 12:10:09 CEST 2012
Hi,
I do have replicates, but not many. The offsets are my the number of
replicates actually, i misled myself by thinking i could add the counts of
the replicates all up and then go further with the offset function. I
decided to split up my experiments in order to interpret them, they were
actually from the beginning split up experiments. Because i thought i could
see if the bees reacted in a same manner to the different experiments i
thought i could analyse it with an interaction factor to reveal whether this
was true. But i want now want to analyse them apart so i can draw
conclusions from the both experiments apart.
I did the following with the counts from p1, including the replicates so i
have only the type of field-margin as a variable, as i was only interested
in this from the beginning:
mengsel count
C 39
C 38
A 79
A 96
A 278
D 15
D 15
B 322
B 449
B 262
a.data.p1<-read.table("a.data.p1.txt",header=TRUE,sep="")
a.data.p1
fit.sat.a.p1<-glm(count~mengsel,data=a.data.p1,family=poisson)
anova(fit.sat.a.p1,test="Chisq")
fit.main.a.p1<-glm(count~1,data=a.data.p1,family=poisson)
anova(fit.sat.a.p1,fit.main.a.p1,test="Chisq")
extractAIC(fit.sat.a.p1)
extractAIC(fit.main.a.p1)
summary(fit.sat.a.p1)
This tells me that the saturated model is better explaning then the other
so:
Call:
glm(formula = count ~ mengsel, family = poisson, data = a.data.p1)
Deviance Residuals:
Min 1Q Median 3Q Max
-6.4531 -3.7799 -0.0404 0.0603 9.2385
Coefficients:
Estimate Std. Error z value Pr(>|z|)
(Intercept) 5.01728 0.04698 106.79 <2e-16 ***
mengselB 0.82433 0.05635 14.63 <2e-16 ***
mengselC -1.36662 0.12327 -11.09 <2e-16 ***
mengselD -2.30923 0.18852 -12.25 <2e-16 ***
---
Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
(Dispersion parameter for poisson family taken to be 1)
Null deviance: 1385.58 on 9 degrees of freedom
Residual deviance: 202.01 on 6 degrees of freedom
AIC: 273.15
Number of Fisher Scoring iterations: 5
How can i produce a graph for this?
I am worried that i still do not have enough replicates to actually draw
descent conclusions or conclusions at all...in my second experiment i do not
have replicates for 2 out of four types of field margins, for the other two
i only have 2 replicates.
this being the counts from the second experiment:
C 3 p2
C 1 p2
A 90 p2
A 29 p2
D 0 p2
B 157 p2
thanks,
babs
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