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

Unless `Sepal.Length` and `Species` are objects saved in your environment, you haven't done anything to tell `mean` where that data should be coming from. This is basically a typo — camille, Nov 25 '19 at 00:09
mosaic:::mean(Sepal.Length ~ Species,data=iris), you still need to provide a dataframe — StupidWolf, Nov 26 '19 at 00:24

score 2 · Answer 1 · answered Nov 24 '19 at 23:44

2

We need to specify the data

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

answered Nov 24 '19 at 23:44

akrun

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I think this answer should move to [linked](https://stackoverflow.com/questions/11562656) post. – zx8754 Nov 25 '19 at 07:55
@zx8754 I think the question is specifically about `mosaic::mean` – akrun Nov 25 '19 at 18:06

score 1 · Answer 2 · answered Nov 24 '19 at 23:42

1

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

answered Nov 24 '19 at 23:42

dc37

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score 1 · Accepted Answer · answered Nov 25 '19 at 00:09

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

answered Nov 25 '19 at 00:09

G5W

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Iris dataset mean() by species

3 Answers3