The applicability of this new teaching method will be tested among students of different age groups.

applicability 是名词，由形容词 applicable（适用的）加上名词后缀 -ity 构成。applicable 来自动词 apply（应用），字面意思是"能够被应用的"。 applicability 指"适用性"，即某事物在不同情况下能够被有效应用的程度或范围。