Plot Error Bars
Add vertical error bars to an existing plot or makes a new plot with error bars.
errbar(x, y, yplus, yminus, cap=0.015, main = NULL,
sub=NULL, xlab=as.character(substitute(x)),
ylab=if(is.factor(x) || is.character(x)) ""
else as.character(substitute(y)),
add=FALSE, lty=1, type='p', ylim=NULL,
lwd=1, pch=16, errbar.col, Type=rep(1, length(y)),
...)x |
vector of numeric x-axis values (for vertical error bars) or a factor or
character variable (for horizontal error bars, |
y |
vector of y-axis values. |
yplus |
vector of y-axis values: the tops of the error bars. |
yminus |
vector of y-axis values: the bottoms of the error bars. |
cap |
the width of the little lines at the tops and bottoms of the error bars
in units of the width of the plot. Defaults to |
main |
a main title for the plot, passed to |
sub |
a sub title for the plot, passed to |
xlab |
optional x-axis labels if |
ylab |
optional y-axis labels if |
add |
set to |
lty |
type of line for error bars |
type |
type of point. Use |
ylim |
y-axis limits. Default is to use range of |
lwd |
line width for line segments (not main line) |
pch |
character to use as the point. |
errbar.col |
color to use for drawing error bars. |
Type |
used for horizontal bars only. Is an integer vector with values |
... |
other parameters passed to all graphics functions. |
errbar adds vertical error bars to an existing plot or makes a new
plot with error bars. It can also make a horizontal error bar plot
that shows error bars for group differences as well as bars for
groups. For the latter type of plot, the lower x-axis scale
corresponds to group estimates and the upper scale corresponds to
differences. The spacings of the two scales are identical but the
scale for differences has its origin shifted so that zero may be
included. If at least one of the confidence intervals includes zero,
a vertical dotted reference line at zero is drawn.
Charles Geyer, University of Chicago. Modified by Frank Harrell,
Vanderbilt University, to handle missing data, to add the parameters
add and lty, and to implement horizontal charts with differences.
set.seed(1)
x <- 1:10
y <- x + rnorm(10)
delta <- runif(10)
errbar( x, y, y + delta, y - delta )
# Show bootstrap nonparametric CLs for 3 group means and for
# pairwise differences on same graph
group <- sample(c('a','b','d'), 200, TRUE)
y <- runif(200) + .25*(group=='b') + .5*(group=='d')
cla <- smean.cl.boot(y[group=='a'],B=100,reps=TRUE) # usually B=1000
a <- attr(cla,'reps')
clb <- smean.cl.boot(y[group=='b'],B=100,reps=TRUE)
b <- attr(clb,'reps')
cld <- smean.cl.boot(y[group=='d'],B=100,reps=TRUE)
d <- attr(cld,'reps')
a.b <- quantile(a-b,c(.025,.975))
a.d <- quantile(a-d,c(.025,.975))
b.d <- quantile(b-d,c(.025,.975))
errbar(c('a','b','d','a - b','a - d','b - d'),
c(cla[1],clb[1],cld[1],cla[1]-clb[1],cla[1]-cld[1],clb[1]-cld[1]),
c(cla[3],clb[3],cld[3],a.b[2],a.d[2],b.d[2]),
c(cla[2],clb[2],cld[2],a.b[1],a.d[1],b.d[1]),
Type=c(1,1,1,2,2,2), xlab='', ylab='')Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.