Write the tense and form of the underlined verb. the arithmetic mean has been used frequently in statistics. (has been used is the underlined verb). i need to know what's the form and what's the tense. if possible, tell me the difference between the two.

had been used is  the past perfect tense  in a passive voice

in an active voice, it would be "had used"

she had written a letter to Rita (active voice)
A letter had been written to Rita (passive voice)

The arithmetic mean had been used frequently in the statistics (passive V.)
They had used frequently arithmetic mean in the statistics (active V.)

so the tense is past perfect in passive voice

hope I helped !!

The answer is the father was relieved, the officer was tired.

Pardon me. to answer questions like this, we would have needed more information. for starters, two sentences from the excerpt that came with the question.