Hi
I am trying to do a logistic regression on a small data file yet when i get
up to plotting the first set of graphs instead of 4 I only get one graph,
and some error messages. Yet it still looks like the program is doing
something due to the "blue wheel" of the mouse. Below is the script copied
from R and where I get up to before the message occurs. The data set is
based on how accurate dogs are at giving a trained response when finding
drugs.
D=dogs, P= phase of test, NF= number found, NTA= times they gave the trained
alert, NA= times they did not give the alert, R= reliability in %
> file.choose()
[1] "E:\\Rhome exam\\question4\\table1Q4.txt"
> tort<-read.table("E:\\Rhome exam\\question4\\table1Q4.txt")
> tort
D P NF NTA Na R
1 1 1 27 8 19 30
2 1 2 29 722 24
3 2 1 30 16 14 53
4 2 2 26 25 1 96
> summary(glm(cbind(NTA,NF-NTA)~P,tort,family=binomial))
Call:
glm(formula = cbind(NTA, NF - NTA) ~ P, family = binomial, data = tort)
Deviance Residuals:
1 2 3 4
-1.339 -3.727 1.236 4.511
Coefficients:
Estimate Std. Error z value Pr(>|z|)
(Intercept) -0.9671 0.6022 -1.606 0.1082
P 0.6487 0.3830 1.694 0.0903 .
---
Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
(Dispersion parameter for binomial family taken to be 1)
Null deviance: 40.462 on 3 degrees of freedom
Residual deviance: 37.556 on 2 degrees of freedom
AIC: 54.505
Number of Fisher Scoring iterations: 4
> anova(glm(cbind(NTA,NF-NTA)~P,tort,family=binomial),test="Chisq")
Analysis of Deviance Table
Model: binomial, link: logit
Response: cbind(NTA, NF - NTA)
Terms added sequentially (first to last)
Df Deviance Resid. Df Resid. Dev Pr(>Chi)
NULL 3 40.462
P 1 2.9064 2 37.556 0.08823 .
---
Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
> par(mfrow=c(2,2))
> plot(glm(cbind(NTA,NF-NTA)~P*factor(D)+Na,tort,family=binomial))
Error in qqnorm.default(rs, main = main, ylab = ylab23, ylim = ylim, ...) :
y is empty or has only NAs
In addition: Warning messages:
1: Not plotting observations with leverage one:
1, 2, 3, 4
2: In min(x) : no non-missing arguments to min; returning Inf
3: In max(x) : no non-missing arguments to max; returning -Inf
>
I have tried multiple ways of swapping and changing the factors around in
the equation yet I am still no further forward. Can anyone please help and
give me a hint as to where im going wrong?
Much appreciated in advance
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