Where the data come from
The measurements are from the Palmer Penguins data package. The data were collected by Kristen Gorman and the Palmer Station LTER program.
How this selection was made
Selection: the first six records with all four body measurements present for each species, in the source file's order. Record numbers count data rows, excluding the CSV header. All 18 selected records are from 2007.
Missing measurements were not replaced with zeros. The selection is useful for a table exercise, but it is not a random or representative sample.
Differences could be connected with species, sex, island, or other conditions. This small comparison cannot separate all of those factors.