Aresearcher is interested in estimating the average salary of police officers in a large city. she wants to be 99% confident that her estimate is correct. if the standard deviation is $1050, how large a sample is needed to get the desired information and to be accurate within $200?

Peter applied to an accounting firm and a consulting firm. he knows that 30% of similarly qualified applicants receive job offers from the accounting firm, while only 20% of similarly qualified applicants receive job offers from the consulting firm. assume that receiving an offer from one firm is independent of receiving an offer from the other. what is the probability that both firms offer peter a job?