You used the k-Nearest Neighbors method for estimation (e.g., estimate the credit score for a new customer). You set k=1 to 20 and the data mining software reported the best k=5. The table below gives the 5 nearest neighbors in the training set for a new observation and the credit score for each neighbor. Answer the following questions based on the above information. Question 18 (4 points) The best k achieves the smallest on the validation set. The best k achieves the smallest on the validation set. root mean squared error class 1 error rate overall error rate class 0 error rate Question 19 (4 points) For the new customer, the estimated credit score = 623 600 619 For the new customer, the estimated credit score = 623 600 619 605 615 628