Using R for Introductory Statistics : John Verzani

Appendix E 372> ourhist(x)It works fine. But what if we wanted to use a different rule for breaks=? It would be niceto be able to override our settings. One way would be to define a breaks= argument:ourhist = function(x,breaks) {hist(x,breaks = breaks, probability = TRUE)lines(density(x))}A typical usage yields> ourhist(x)Error in hist.default(x, breaks = breaks, probability =TRUE) :Argument "breaks" is missing, with nodefaultOops, we haven’t set a default value for breaks and we didn’t directly specify one, suchas ourhist (x,"Scott"). Immediately after we list the argument for the function, we cansupply a default value in the pattern name=value. Try this:ourhist = function(x,breaks="Scott") {hist(x,breaks=breaks,probability=TRUE)lines(density(x))}Bothourhist(x) and ourhist (x,breaks="Sturges") will now work. The two commandsshow a difference in the number of bins, the second using the Sturges rule to compute thenumber instead of the default.Still, the histogram drawn looks bland. Let’s add some color to it—the color purple.The hist () function has a col= argument to set the color of the boxes. We can make thecolor be purple by default with this modification:ourhist = function(x,breaks="Scott",col="purple”) {hist(x,breaks=breaks,probability=TRUE,col=col)lines(density(x))}Trying it out gives> ourhist(x)> ourhist(x,"Sturges") # use different bin rule> ourhist(x,"Sturges","green") # green before purple> ourhist(x,"green") # OopsError in match.arg(tolower(breaks), c("sturges", "fd","freedman-diaconis", : ARG should be one of sturges,fd,