Answer: The percent error in the player's guess is 9.5%.
Explanation:
Given : A basketball player guesses her team will score 57 points during the game. 
The player's team actually scores 63 points. 
i.e. The actual core = 63 points
The estimated score = 57 points
Then , the percent error in the player's guess would be :

Hence, the percent error in the player's guess is 9.5%.