[R] hist{graphics}

[Duncan Murdoch]

On 12/07/2019 11:38 a.m., Steven wrote:
> Never mind. Thanks.
> 
> I found that adding parameter right=F to the call fixes it.

Drawing a histogram of discrete data often leads to bad results. 
Histograms are intended for continuous data, where no observations fall 
on bin boundaries.

You often get a more faithful representation of discrete data using 
something like

plot(table(x))

Duncan Murdoch

> 
> On 2019/7/12 下午 05:10, Steven wrote:
>> # Can someone help with this simple frequency histogram problem (n = 15)?
>> # I use four class limits: [90,95], [95,100], [100,105], [105,110].
>> # These coincide with the limits obtain by pretty {base}.
>> # Proper frequencies would be: (1,5,6,3).
>> # But hist{graphics} gives me a histogram showing frequencies (1,8,3,3),
>> # with or without argument break = ...
>> # Replicable codes below. Thanks.
>>
>> set.seed(123)
>> x<-rnorm(15,mean=100,sd=5); x<-as.integer(x)
>> x<-sort(x)
>> x
>> breaks<-seq(90,110,by=5); breaks
>> pretty(x,n=5) # pretty {base}
>> x.cut<-cut(x,breaks,right=F) ; x.cut
>> freq<-table(x.cut); cbind(freq)
>> hist(x,breaks=breaks) # hist {graphics}
>> hist(x)
>>
>>
>>
> 
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