How dose an observation about an object differ from an inference about that object?

Observation gathers qualitative sensory data about an object and inference gathers data about an object based on prior experience or present knowledge and research.

I hope this helps.

An inference uses observations to make a guess on what happened. For example the man walked in carrying an umbrella and was soaking wet, that is an inference.

An observation uses your senses to determine what happened. For example you loked out the window and saw that it was raining, that is an observation.