"This contradicts the passage argument about THE committee's conclusion." I agree with Noel that your statement is not clear enough. It's important to point out the bias found by the professor in the lecture. I would say something like this... "Although the committee found Peary's account persuasive, the professor concluded their decision was biased because the committee consisted of Peary's friends who did not spend enough time investigating." You can also say it this way... "The committee found Peary's account persuasive, however, the professor concluded their decision was biased because the committee consisted of Peary's friends who did not spend enough time investigating." (Numerous ways of stating these two points are possible.)

Not clear enough. I would recommend saying something like: "Information presented in the professor's lecture discounts the "persuasive" conclusion reached by the committee.