The associate dean of the college of business at Poly has succumbed to faculty pressure to purchase a new fax machine, although she has always contended that the machine would have minimal use. She has estimated that the machine will be used only 20% of the time. Now that the machine has been installed, she has asked the students in the introductory OM course to conduct a work sampling study to see what proportion of time the new fax machine is used. She wants the estimate to be within 3% of the actual proportion, with a confidence level of 95%. Determine the sample size for the work sample.