"A company of accountants has branches in five regions, Port Louis (PL), Curepipe (CPE), Beau Bassin (BB), Rose Hill (RH) and Quatre Bornes (QB). It employs the following number of staff at each branch - 120 at PL, 80 at CPE, 40 at BB, 60 at RH, 100 at QB.
Suppose the company wishes either to involve every employee, or conduct a survey of 20% of its employees. Advise how the sample for surveying should be best selected by each of the following sampling methods, commenting on the advantages of each:
a. Census.
b. Cluster sampling.
c. Simple random sample.
d. Stratified random sample.
e. Systematic sample.