Final answer:
The word used incorrectly is 'were'.
Step-by-step explanation:
The word used incorrectly in the given statement is 'were'.
The correct sentence should be: The procedure for giving injections was explained thoroughly to the student nurses.
In this case, 'procedure' is a singular noun, so the verb 'was' should be used instead of 'were', which is a plural form of the verb. In the original sentence, there is a subject-verb agreement error. The subject "procedure" is singular, so it should be paired with the singular verb "was" instead of the plural "were." This is because "procedure" refers to a single process or action.
The corrected sentence emphasizes that the explanation of the injection procedure was given in detail to the student nurses.
Learn more about Subject-Verb Agreement