Employing the summary() function is an easy way to take a first immediate look at your data distribution. You just have to pass to the function of the data frame you are working with, to get as a result a print out of the following summary statistics for each of the columns:

• minimum
• first quartile
• median
• mean
• third quartile
• maximum

Let's try, for instance, to apply this function to the Toothgrowth dataset, which is one of the built-in datasets within base R (if you want to discover more of those datasets, just run data() within your R console):

summary(ToothGrowth)
      len        supp         dose      
 Min.   : 4.20   OJ:30   Min.   :0.500  
 1st Qu.:13.07   VC:30   1st Qu.:0.500  
 Median :19.25           Median :1.000  
 Mean   :18.81           Mean   :1.167  
 3rd Qu.:25.27           3rd Qu.:2.000  
 Max.   :33.90           Max.   :2.000  

As you can see, we find here for every and each variable, which are len, supp, and dose, the summary statistics descriptor. One final, relevant note: since the supp variable is a categorical one, for this variable we find the two different values the variable assumes, which are OJ and VC, together with their frequency, which is 30 for both of them. A lot of information for just one function, isn't it?