Tata Motors of India is marketing a new vehicle that retails for only $2,200. The vehicle will carry two persons and has a body made of fiberglass. It is designed in component parts so that if a part is broken, you can easily disassemble the part and replace it with a new one ordered from Tata. Tata realizes that it will take some time for countries to allow the small vehicle on public roads due to safety requirements.
However, Tata sees an immediate market among business firms who need inexpensive yet reliable vehicles to transport personnel around large manufacturing or warehousing facilities. One Tata manager stated: "Ninety percent of the time, company cars are used to transport only one or two persons and much of their travel is confined to the plant premises." "The new Tata vehicle will not replace the large company cars but can reduce the number of company cars a firm must buy by a substantial amount, thus saving tremendous amounts of money." Executives at Tata are interested in a sales estimate in Great Britain, their first targeted market outside of India. They will construct a sales forecast based upon a survey of companies and they know that demand will vary substantially, depending on the size of the company. Small firms will not want any vehicles, medium-sized firms may want about 5 or 10 vehicles, and large firms may want 20 to 100 vehicles. Secondary data is available that allows Tata to identify all firms in Great Britain and to know the size of the firm. If a survey is conducted to predict demand for the new Tata vehicle among business firms, which of the following sampling methods would be most appropriate?
a. simple random sample
b. judgment sample/purposive/key informant
c. stratified sample
d. cluster, area sample