Summary Statistics of Data Frame in R – Descriptive Stats Tutorial (2 Examples)

In this article, I’ll explain how to get descriptive statistics for the columns of a data frame in the R programming language.

Example Data

data(iris)                           # Example data
head(iris)
#   Sepal.Length Sepal.Width Petal.Length Petal.Width Species
# 1          5.1         3.5          1.4         0.2  setosa
# 2          4.9         3.0          1.4         0.2  setosa
# 3          4.7         3.2          1.3         0.2  setosa
# 4          4.6         3.1          1.5         0.2  setosa
# 5          5.0         3.6          1.4         0.2  setosa
# 6          5.4         3.9          1.7         0.4  setosa

Example 1: Get Summary Statistics Table for Data Frame

summary(iris)                        # Computing a summary statistics table
#   Sepal.Length    Sepal.Width     Petal.Length    Petal.Width   
#  Min.   :4.300   Min.   :2.000   Min.   :1.000   Min.   :0.100  
#  1st Qu.:5.100   1st Qu.:2.800   1st Qu.:1.600   1st Qu.:0.300  
#  Median :5.800   Median :3.000   Median :4.350   Median :1.300  
#  Mean   :5.843   Mean   :3.057   Mean   :3.758   Mean   :1.199  
#  3rd Qu.:6.400   3rd Qu.:3.300   3rd Qu.:5.100   3rd Qu.:1.800  
#  Max.   :7.900   Max.   :4.400   Max.   :6.900   Max.   :2.500  
#        Species  
#  setosa    :50  
#  versicolor:50  
#  virginica :50  
#                 
#                 
#

Example 2: Get Summary Statistics by Group

aggregate(Sepal.Length ~ Species,    # Computing the mean by group
          iris,
          mean)
#      Species Sepal.Length
# 1     setosa        5.006
# 2 versicolor        5.936
# 3  virginica        6.588

Further Resources

Have a look at the following list of R programming language tutorials. They focus on topics such as variables and groups:

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