1.49 An article titled “Surface Sampling in Gravel Streams” (Journal of Hydraulic Engineering, April 1993) discusses grid sampling and areal sampling.

Grid sampling involves the removal by hand of stones found at specific points. These points are established on the gravel surface by using either a wire mesh or predetermined distances on a survey tape. The material collected by grid sampling is usually analyzed as a frequency distribution. An areal sample is collected by removing all the particles found in a predetermined area of a channel bed. The material recovered is most often analyzed as a frequency distribution by weight. Would you categorize these sample designs as judgment samples or probability samples?