Based on the results of the second set of tests, it appears that the function f(x) is highly selective for words related to astronomy and space. Words like "planet," "telescope," "satellite," and "astronaut" have relatively high values closer to 1, implying a strong association with this concept. In contrast, words from unrelated fields have considerably lower values.

[DESCRIPTION]: The function f(x) is selective for words associated with astronomy and space exploration, assigning higher values to words closely related to these concepts and lower values to unrelated words.