Final answer:
The truthfulness of the statement about the lab assignment's external data file name being 'testdata' and unchangeable depends on the specific instructions given for the assignment. The file name might be fixed or flexible based on the requirements provided.
Step-by-step explanation:
The statement regarding the invariability of the external data file name testdata for a lab assignment cannot be universally classified as true or false without further context. In the realm of computer science or programming lab assignments, file names are often specified by the requirements of the assignment. If the instructions explicitly state that the external data file must be named testdata and not vary, then the statement would be true. Otherwise, if the lab guidelines allow for different file names or no specification is provided, the statement would be false. It's crucial to carefully read the lab instructions to determine the correct file naming conventions to be followed.