Iris dataset mean() by species

Question

I want to create some mean of sepal.length, but divided by species. Using mosaic package

mean(Sepal.Length~Species)

It didn't work

Answer 1

A base R solution

aggregate(Sepal.Length ~ Species, data=iris, mean)
     Species Sepal.Length
1     setosa        5.006
2 versicolor        5.936
3  virginica        6.588

Answer 2

Using dplyr, you can do:

library(dplyr)
iris %>% group_by(Species) %>% summarise(Mean = mean(Sepal.Length))

# A tibble: 3 x 2
  Species     Mean
  <fct>      <dbl>
1 setosa      5.01
2 versicolor  5.94
3 virginica   6.59

Answer 3

We need to specify the data

mosaic::mean(Sepal.Length ~ Species, data = iris)
#    setosa versicolor  virginica 
#     5.006      5.936      6.588