
















• 
Vary the size of
a hypersphere around each test point



so that exactly
K training datapoints fall inside the hyper


sphere.



– 
Does
this give a fair estimate of the density?


• 
Nearest
neighbors is usually used for classification or



regression:



– 
For
regression, average the predictions of the K



nearest
neighbors.



– 
For
classification, pick the class with the most votes.



• 
How
should we break ties?

