Answer:
Vestibule Training.
Step-by-step explanation:
Vestibule training is a method for training where staff is trained near the job. This means staff should be trained inside the walls of office or factory. This method includes training the staff near to actual practical working environment. This technique is easy to use and staff is trained to learn something new while staying in working environment.
In the given scenario the new chemists are given rejected samples to work on and learn the techniques before actually working on the manufacturing of medicines. This is example of Vestibule training. This method is cost effective and enables the chemists to learn new techniques in the working environment.