Selecting samples from populations.Grafstrom and Schelin (2014) conducted a study evaluating the selection of samples from populations.They identified that "the main goal (of selecting samples) is to select a sample so that various parameters can be estimated with good precision (Grafstrom & Schelin, 2014, p.277).

(a) What does a parameter describe?

(b) What are the characteristicsin a sample called that are used to estimate the various parameters that the authors refer to?