How to find the sample size for the true population mean.
A manufacturer of dodge balls utilizes a machine to inflate its new balls to a pressure of 13.5 pounds (σ =0.1). When the machine is properly calibrated and the mean inflation pressure s 13.5 pounds, but uncontrollable factors can cause the pressure of individual dodge balls to vary. For quality control drives the manufacturer wishes to estimate the mean inflation pressure to within 0.025 pounds of its true value with a 99% confidence. What model size should be used?