Anything that's unanalyzed hasn't been studied carefully or examined thoroughly. To complete your lab report, you'll need to take the raw, unanalyzed data from your experiment and draw conclusions about it
When you analyze something, you slowly and deliberately examine it, whether it's an idea, a poem, an emotion, or a scientific theory. So when these things are unanalyzed, they haven't been looked at in this deliberate way. Some people prefer to leave controversial subjects unanalyzed, but it's often important to study and discuss them — in other words, to analyze them.