In what way did rannan make an error in his scientific process

He should not use his opinion as evidence

The answer is he should not use his opinion as evidence.

Explanation:

Rannan decides to perform a scientific experiment. He writes out a systematic process that involves him making observations and then forming his opinion about those observations. He collects his opinions together and uses them to show that his findings are supported by evidence.

Thus Rannan make an error in scientific process because he should not use his opinion as evidence.