On 17/03/15 13:34, varin sacha wrote:
Dear R-Experts,
I can easily plot an histogram and its density curve. But when I try
to add the Gauss curve on the histogram with the following Rcode here
below, I don't get it. What is wrong ? Or what is missing in my code
?
Coherency and appropriate checking of syntax.
* Your call to lines() is *inside* the call to seq(), whence it gets
ignored.
* Your call to seq() should specify some reasonable values for "length"
or "by", otherwise "x" has far too few values and you get a very jagged
curve.
* You should not jumble a whole lot of commands together. This leads to
the sort of mistakes that you made. Do one thing at a time. Keep your
commands brief. You will then have far less tendency to make mistakes
and a far easier time in detecting where mistakes have been made if you
do make them.
* There is no such thing as "the" Gauss curve. There is an uncountably
infinite number of Gauss curves.
* As Jeff Newmiller told you, *do* provide a *reproducible* example when
you ask a question. (Nobody but *you* has the data set "newdata".)
Neither R nor the members of this list can mind-read.
cheers,
Rolf Turner
##Plot an histogram h=hist(newdata$math.test, prob=TRUE, col="blue",
border="white", xlab="Note test math", ylab="Densité", main="Test
math")
##Add the density curve on the histogram
lines(density(newdata$math.test,na.rm=TRUE),lwd=2,col="orange")
##Add the Gauss curve on the histogram x <- seq(from =
min(newdata$math.test, na.rm=TRUE), to = max(newdata$math.test,
na.rm=TRUE), lines(x, dnorm(x, mean(newdata$math.test, na.rm = TRUE),
sd(newdata$math.test, na.rm = TRUE)))
--
Rolf Turner
Technical Editor ANZJS
Department of Statistics
University of Auckland
Phone: +64-9-373-7599 ext. 88276
Home phone: +64-9-480-4619
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