In the Case Study, we interpreted the phrase “much less than” to mean a measurement that is 2 or more standard deviations below the mean. For Exercises 115–118, suppose we interpret the phrase “much less than” to mean a measurement that is 3 or more standard deviations below the mean.

Question 7.118

118. The Master of the Mint wanted to choose a mean value so that his chances of failing the Trial of the Pyx were 25%. Which mean value is this?