[R] hist{graphics}

[peter dalgaard]

Also checkout MASS::truehist or simply consider setting breaks so as not to coincide with data values. (hist() not doing something like this, but instead actively aiming for pretty breaks is something of a design bug in my book, but ancient history and not easy to change at this point in time.)

-pd

> On 13 Jul 2019, at 11:29 , Duncan Murdoch <murdoch.duncan using gmail.com> wrote:
> 
> 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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> 
> ______________________________________________
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-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
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