The comparison of mean crowding between two groups.

The infrapopulation size, or crowding, is an important measure in parasitology because of its impact on many facets of parasite biology. However, crowding values are difficult to handle statistically because of dependencies. Therefore, a bootstrap procedure was proposed in order to compare crowding between 2 groups or samples of hosts. Here, we propose Lepage's location-scale test based on intensities as an alternative to test whether there is a difference in mean crowding. Simulation results indicate that Lepage's test is superior to the bootstrap, even when sample sizes are large as needed for the bootstrap procedure. Lepage's test, however, can also be applied with moderate or small sample sizes.