[R] Stacked geom_bar with aggregated SE -ggplot2
Olivia Burge
olivia.burge at gmail.com
Tue Apr 30 14:20:59 CEST 2013
Hi there,
I've been battling with an extension of this in my own data: getting
appropriate error bars once data is stacked in a bar graph.
(original question:
http://r.789695.n4.nabble.com/ggplot2-se-variable-in-geom-errorbar-s-limits-
td3311176.html). It wouldn't let me reply to that thread.
A modification of the earlier answer:
data(diamonds)
diamonds_df <- ddply(diamonds, .(cut, color), summarise,
mean_price = mean(price),
se_price = sd(price)/sqrt(length(price))
)
limits <- aes(ymax = mean_price + se_price, ymin = mean_price - se_price)
a<-ggplot(diamonds_df, aes(x = cut, y = mean_price, fill=color)) +
geom_bar(position=position_stack(width=0.9))
a
Then attempting to add error bars:
a+ geom_errorbar(limits, position=position_stack(width=0.9), width=0.9)
I have tried:
r + stat_sum_df("mean_cl_normal", geom = "errorbar"), using the aggregation
function in http://www.stanford.edu/~paunesku/, using ddplyr but haven't
managed to work out a way of specifying the error bars to R. In my case I
would like to use an error bar analogous to each value of "cut" in the data
example. When I calculate the SEs appropriately ggplot2 won't stack.
This is first time posting and I've scoured the various forums and websites
for a worked example.
In case it is relevant, my response variable is fitted germination of an
lmer model ("germination"), x is a categorical variable (treatment, with 3
levels), and I am using a categorical variable ("species") to stack.
Kind regards,
Olivia
MSc student
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