绘图错误-半正态图[

Question

Hopefully this is a straight-forward question. I'm not sure where there error is--it seems like a R is not working here. I've restarted R and reproduced the error, so I'm not sure what's going on.

Problem: I have some data, and am trying to produce a halfnormal plot for the effects. Ho-hum, everything's going fine... except the most significant effect isn't showing up in my half normal plot:

# load data
dat2 <- read.table("http://www.stat.ucla.edu/~hqxu/stat201A/data/solder2.dat")
# required library
library(faraway)
# rename vars
names(dat2) <- tolower(names(dat2))
# create full model
a1.1 <- aov(defects ~ a + b + c + d + e + f + g + h + a:b + a:e + a:f + a:g + a:h +
              b:f + b:g + b:h + c:f + c:g + c:h + d:f + d:g + d:h + e:f + e:g + e:h,data=dat2)
# plot effects
halfnorm(a1.1$coef[-1], nlab= length(a1.1$coef[-1])/3-1, labs= names(a1.1$coef[-1]),
         ylab= "abs|Factor Effects|",
         main= "Half Normal Plot") +  qqline(abs(a1.1$coef[-1]))

As you can see, my plot is missing effect C. The largest one. Please let me know if you're not able to reproduce this error. It seems very odd to me.

# effects from the model, descending
a1.1$coef[-1][order(abs(a1.1$coef[-1]), decreasing=T)][1:10]
      c       a       e     a:h     b:f     c:f     a:f     c:g     c:h     a:g 
 56.875 -27.500  22.750  13.125 -13.000 -12.750  12.500  12.375   7.375   7.000

EDIT As expected, and noted below, this was simple. Here's the correct code:

halfnorm(a1.1$coef[-1], nlab= round(length(a1.1$coef[-1])/3,0), labs= names(a1.1$coef[-1]),
         ylab= "abs|Factor Effects|",
         main= "Half Normal Plot") +  qqline(abs(a1.1$coef[-1]))

Answer 1

Your value of nlab doesn't end up being an integer. Looking at the code this gives the function an issue and in some cases causes the last effect to not get a label. If you round the value or just set it directly to an integer your problem goes away.