The Next Questions Are Based on the Following Information

The Next Questions Are Based On The Following Information:
A pharmaceutical manufacturer is concerned that the mean impurity concentration in pills should not exceed 3%.It is known that from a particular production run impurity concentrations follow a normal distribution with a standard deviation 0.4%.A random sample of 36 pills from a production run was checked,and the sample mean impurity concentration was found to be 3.09%.
-In the context of this problem,explain why a one-sided alternative hypothesis is more appropriate than a two-sided alternative.