Identify the sampling techniques​ used, and discuss potential sources of bias​ (if any). Explain.
Chosen at​ random,
640
customers at
a
bank
are contacted and asked their opinions of the service they received.
A.
Simple random sampling is​ used, since the business is selecting from its customers at​ random, and all samples of
640
customers have an equal chance of being selected.
B.
Stratified sampling is​ used, since the population of customers is divided into groups and a random sample is selected from each group.
C.
Cluster sampling is​ used, since the population of customers is divided into groups and several groups are selected and all of their members sampled.
D.
Convenience sampling is​ used, since the business is selecting from its customers that are easiest to reach.
E.
Systematic sampling is​ used, since customers are selected at fixed intervals.