SURVEY SAMPLING. Gladstone and Associates is conducting a survey of 2000 investors for the financial advising firm of William and Ryde to determine satisfaction with their services. The investors are to be divided into four groups:
Group I: Large investors with William and Ryde
Group II: Small investors with William and Ryde
Group III: Large investors with other firms
Group IV: Small investors with other firms The groups are further subdivided into those that will be contacted by telephone and those that will be visited in person. Due to the different times involved in soliciting information from the various groups, the estimated cost of taking a survey depends on the group and method of survey collection. These are detailed in the following table.
minimize Gladstone and Associates’ overall total estimated cost if:
• At least half of those surveyed invest with William and Ryde.
• At least one-fourth are surveyed in person.
• At least one-half of the large William and Ryde investors surveyed are contacted in person.
• At most 40% of those surveyed are small investors.
• At least 10% and no more than 50% of the investors surveyed are from each group.
• At most 25% of the small investors surveyed are contacted in person.