Question

A nationwide furniture company wants to survey their customers to determine whether or not they are providing quality customer service across the United States. They have 140 stores with an average of about 3,000 customers each per month.Which survey group would produce a valid sample?
90 customers from one store
90 customers from each store
90 customers from the best performing stores
90 customers from the stores on the west coast.

Answer 1

90 customers from each store