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

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

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

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  
#                 
#                 
#

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 # # #

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

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