7.1 a A complete list of all directors of large manufacturing firms could be purchased from an organisation that specialised in selling such lists to use as the sampling frame. Alternatively, a list that contained only those selected for the sample could be purchased to reduce costs. These data are usually in a format suitable for being read by word-processing and database computer software, and so they could easily be merged into standard letters such as those included with questionnaires. b A complete list of accountants, or one that contained only those selected for the sample, could be purchased from an organisation that specialised in selling such lists. Care would need to be taken regarding the precise composition of the list to ensure that it included those in private practice as well as those working for organisations. Alternatively, if the research was interested only in qualified accountants then the professional accountancy bodies’ yearbooks, which list all their members and their addresses, could be used as the sampling frame. c The personnel records or payroll of Cheltenham Gardens Ltd could be used. Either would provide an up-to-date list of all employees with their addresses.