Data Sufficiency

The Department of Environmental Protection measured the volume of water in 10 similarly sized reservoirs in State X and found that the standard deviation of their volumes at the start of the year was a certain value. Was the standard deviation of those 10 volumes the same at the end of the year?

(1) During the year the volume of water in each reservoir decreased by 5 million cubic gallons.

(2) During the year the volume of water in each reservoir decreased by 20%.

Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient to answer the question asked

Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient to answer the question asked

Both statements (1) and (2) TOGETHER are sufficient to answer the question asked; but NEITHER statement ALONE is sufficient

EACH statement ALONE is sufficient to answer the question asked

Statements (1) and (2) TOGETHER are NOT sufficient to answer the question asked, and additional data specific to the problem are needed




again same IMO -d,a??