As a general rule, experiments always produce too much data. Some of it is irrelevant. Some of it is wrong. The trick is to separate the useful data from the bad data, and to reduce it to a form that mere humans can understand. That's what good scientists do.
All scientists have expectations and prejudices.
They do experiments expecting to obtain particular results. Of course not. We should only criticize them when there is evidence that they have allowed their prejudices to influence their judgment. There is no question that Eugene Dubois went to Indonesia with the foregone conclusion that a missing link between ape and man existed, and he intended to find it. Evolutionists accepted Java Man as a missing link based on just these two bones.