An auditor examined data flow diagrams in a small portion of system development projects and determined that there were nearly 12% of them with errors. The Vice-President for Development wants a better estimate of the percentage so you are tasked to sample the diagrams produced for the past five years and report back.
a) How large a sample would you have to examine to be 95% certain that your estimate would be within 3% of the actual percentage? Explain how you arrived at your answer.
b) Given your answer to part a), how will you arrive at the estimate that you will report back to the vice-president?