I have a dataframe that stores marks for questions against multiple ids.
ID, Q1, Q2, Q3, Q4, Q5
R1, 4, 3, 3, 2, 1
R2, 3, 2, 3, 2, 4
R3, 5, 1, 3, 4, 3
R4, 1, 3, 3, 5, 3
...
...
I want to plot the average marks of the 5 questions in a single plot.
How do I go about doing this in R using the ggplot2 package? What would be my 'x' and 'y' aesthetics?
You need to start transforming your data. Here I make a data.frame with one column for the labels and another for the averages and then feed it to ggplot.
library(ggplot2)
col_means <- colMeans(data[paste0("Q", 1:5)])
col_meansdf <- stack(col_means)
col_meansdf
# values ind
# 1 3.25 Q1
# 2 2.25 Q2
# 3 3.00 Q3
# 4 3.25 Q4
# 5 2.75 Q5
ggplot(col_meansdf, aes(x = ind, y = values)) +
geom_col()
# or in one step:
qplot(
x = paste0("Q", 1:5),
y = colMeans(data[paste0("Q", 1:5)]),
geom = "col"
)
Reproducible data:
data <- read.table(
text = "ID, Q1, Q2, Q3, Q4, Q5
R1, 4, 3, 3, 2, 1
R2, 3, 2, 3, 2, 4
R3, 5, 1, 3, 4, 3
R4, 1, 3, 3, 5, 3",
header = TRUE,
sep = ","
)
# or in one step:One-liner with geom_col:
ggplot(data.frame(mean = colMeans(df), question = names(df))) +
geom_col(aes(question, mean))
Data
df <- data.frame(Q1 = c(4,3,5,1),
Q2 = c(3,2,1,3),
Q3 = c(2,2,4,5),
Q4 = c(1,4,3,3))
You can do this with stat_summary after converting from wide to long format. Change geom = "point" at will, see other possible geoms in ?stat_summary.
library(dplyr)
library(ggplot2)
long <- df1 %>%
gather(Question, Answer, -ID)
ggplot(long, aes(Question, Answer)) +
stat_summary(geom = "point", fun.y = mean)
Data.
df1 <- read.csv(text = "
ID, Q1, Q2, Q3, Q4, Q5
R1, 4, 3, 3, 2, 1
R2, 3, 2, 3, 2, 4
R3, 5, 1, 3, 4, 3
R4, 1, 3, 3, 5, 3
")
