<pre>
> df <- data.frame(trt = factor(c(1, 1, 2, 2)), resp = c(1, 5, 
+     3, 4), group = factor(c(1, 2, 1, 2)), se = c(0.1, 0.3, 0.3, 
+     0.2))
> df2 <- df[c(1, 3), ]
> ggplot(df, aes(max = resp + se, min = resp - se, x = trt, fill = group)) + 
+     geom_bar(position = "dodge")
<a href='web/graphics/c956feb0a4be90fd372c6918ed21f4c9.pdf'><img src='web/graphics/c956feb0a4be90fd372c6918ed21f4c9.png' /></a>

> limits <- aes(max = resp + se, min = resp - se)
> p <- ggplot(df, aes(fill = group, y = resp, x = trt))
> p + geom_bar(position = "dodge")
<a href='web/graphics/f9de26c827dd1cb42c4ba57228784a1f.pdf'><img src='web/graphics/f9de26c827dd1cb42c4ba57228784a1f.png' /></a>

> p + geom_bar(position = "dodge") + geom_errorbar(limits, position = "dodge")
<a href='web/graphics/0f7852d15a7f2a96720bb8ebf205330a.pdf'><img src='web/graphics/0f7852d15a7f2a96720bb8ebf205330a.png' /></a>

> p <- ggplot(df2, aes(fill = group, y = resp, x = trt))
> p + geom_bar(position = "dodge")
<a href='web/graphics/7d09d84a517d082d7727e2bcb02e6fb9.pdf'><img src='web/graphics/7d09d84a517d082d7727e2bcb02e6fb9.png' /></a>

> p + geom_bar(position = "dodge") + geom_errorbar(limits, position = "dodge")
<a href='web/graphics/c874bf3014e4141905ae718e1a4327ad.pdf'><img src='web/graphics/c874bf3014e4141905ae718e1a4327ad.png' /></a>

> p <- ggplot(df, aes(colour = group, y = resp, x = trt))
> p + geom_point() + geom_errorbar(limits, width = 0.2)
<a href='web/graphics/41da0ba8432120a3477b0c9ca2453c40.pdf'><img src='web/graphics/41da0ba8432120a3477b0c9ca2453c40.png' /></a>

> p + geom_pointrange(limits)
<a href='web/graphics/903efe5799ab52f1d3e5aa5cf84d3936.pdf'><img src='web/graphics/903efe5799ab52f1d3e5aa5cf84d3936.png' /></a>

> p + geom_crossbar(limits, width = 0.2)
<a href='web/graphics/34d4326704049683e842900d29d745ed.pdf'><img src='web/graphics/34d4326704049683e842900d29d745ed.png' /></a>

> p + geom_line(aes(group = group)) + geom_errorbar(limits, width = 0.2)
<a href='web/graphics/3657410f9caf9df276be4c199fe32f09.pdf'><img src='web/graphics/3657410f9caf9df276be4c199fe32f09.png' /></a>

</pre>
