Body measurements on a sample of 200 (purple) rock crabs (Leptograpsus variegatus) found in the southern subtropical Pacific Ocean. These are small sea crabs that grow at most to about 50 millimetres of shell width.

The objective is to determine whether the sample actually represents two different species of rock crab base only on their physical measurements. See reference for details.

Format

A data frame with 200 rows and 5 variables

front

The length in millimetres of the crab's carapace frontal lobe region just before the "frontal tubercles".

rear

The length in millimetres of the crab's carapace rear.

length

This is a measurement (in mm) of the length of the crab's carapace from front to rear along its centre line.

width

This is a measurement (in mm) of the width of the carapace of the crab at its widest point.

depth

This is a measurement (in mm) of the depth of the crab body.

There are known to be four distinguishable subsets in this data set.

Details

These are physical measurements on the purple rock crab (Leptograpsus variegatus), a large eyed crab found in the southern subtropical Pacific ocean. These are small sea crabs that grow at most to about 50 millimetres of shell width.

Data are a subset of the crabs data set from the MASS package. Only the five size measurements or the crabs are given here and their order has been randomized.

A good data set for cluster analysis

References

N.A. Campbell and R.J. Mahon (1974). "A multivariate study of variation in two species of rock crab of the genus Leptograpsus." Australian Journal of Zoology 22, 417-425. <doi:10.1071/ZO9740417>

Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer. <doi:10.1007/978-0-387-21706-2>

See also

Author

R.W. Oldford