An observation classified as part of a group with a characteristic when it actually does not have the characteristic is termed as a(n)

False-positive.

Explanation:

A false positive is a term that experts use when there is an error in the results of an experiment or test.  Where there seemed to be a condition,  there is no such thing. These observations, which seemed correct but are not, lead to a false positive since we perceive something that is not there.

hygrometers and hair thermometers (often found as part of hygrometers/psychrometers) can be used to measure humidity. barometers are used to measure atmospheric pressure, while anemometers are used to measure wind speed. so the 2nd and 4th choices should be the correct answers.