Sadie does say something new, but does it rise to the level of evidence? She only suggests that his memorization rate might not be constant; she doesn't prove that it is not. While you might be able to argue that the word “evidence” is okay, the word “contradicts” clearly takes things too far. Sadie does not definitively contradict Baram's premise that he will need only 95 more minutes; rather, she raises a question as to whether he can memorize the words in only 95 minutes.