Meanings of unprecise in английском

These observations of mine are admittedly casual and unprecise.

The observations of psychology are always rather unprecise.

History does not usually busy itself with little men and small facts, and is therefore often obscure, unprecise, vague, tiresome.

The quantification of physical activity, however, is difficult as commonly used self-reported measures are biased and rather unprecise point in time measurements.