Take the following as truth: The ratio of occurrence of hydrogen-ammonia planets and these super-dense water-oxygen worlds of theirs over the entire Galaxy--and remember that they have actually conducted a survey of significant sample volumes of the Galaxy which we, without interstellar travel, cannot do--is about 3 to 1.
Then the following statement: "They have used a large sample of volumes." is true, false, or inconclusive?
Answer: True