How do you get an overview of a Data Frame ?
> summary(df) X1 X2 Min. : 1.00 Min. : 1.00 1st Qu.: 3.25 1st Qu.: 3.25 Median : 5.50 Median : 5.50 Mean : 5.50 Mean : 5.50 3rd Qu.: 7.75 3rd Qu.: 7.75 Max. :10.00 Max. :10.00