The way I see it (as someone who knows nothing about statistics), confidence would be the difference between 9/10 vs 900/1000. And/or how much effort you spend

The way I see it (as someone who knows nothing about statistics), confidence would be the difference between 9/10 vs 900/1000. And/or how much effort you spend ramming a square peg in a round hole to have a prediction model. You have a lot of data about donkeys vs elephants. But this contest is between a mule and a mammoth. If you assume a mule is equivalent to a donkey and a mammoth is equivalent to an elephant, the mule has 95% odds in its favor. But you recognize the assumptions so your prediction doesn't have a high confidence.