12.5.39

A certain dry cereal is packaged in 23-oz boxes. The machine that fills the boxes is set sothat, on theaverage, a box contains 23.5 oz. Themachine-filled boxes have contents weights that can be closely approximated by a normal curve. What percentage of the boxes will be underweight(that is, below the stated weight of 23-oz) if the standard deviation is 0.5 oz?

If the standard deviation is 0.5 oz., _____% boxes will be underweight.