The correct answer is C. This was what I initially put, but I later thought that it may be D because the problem does not specify whether it is sample standard dev. or population standard deviation.
In this example, if the population standard deviation was 6, n would be 10. If the sample standard deviation is 6, n would be 11. Thoughts?
My initial response here would be that this is not a sample, because there is no larger population of which this list with n elements is a sample of. So there wouldn’t be a justification to use the sample SD.
Separately, I am not sure if we can say the GRE will always use population or sample standard deviation, but anyone feel free to correct me! I believe population will be overall more common, but you should always run a logic check.
ETS explicitly says on page 14 of https://www.ets.org/pdfs/gre/gre-math-conventions.pdf that it’s population. If they refer to the sample standard deviation, this will be clear.
