One of the several large federal facilities that are used to store the current version of the flu vaccine is to be sampled in a quality control investigation. A systematic sample will be used to estimate the proportion of damaged or improperly sealed vials of the flu vaccine. If the facility contains ???? = 100000 vials of the flu vaccine, determine

(a) the number of vials to be sampled if the desired bound on the error of estimation is ???? = 0.025

(b) the sampling interval ????.

(c) the cost of sampling when ????0 = $9000 and the cost of sampling each unit is $25.