Question: A processor of carrots cuts the green top off each carrot, washes the carrot, and inserts six to a package. Twenty packages are inserted into a box for shipment. To test the mass of the boxes a few were checked. The mean mass was 9.3 kg, the standard deviation 0.23 kg. How many boxes must the processor sample to be 95 percent confident that the sample mean does not differ from the population mean by more than 0.09 kg.