I ran into a 2019-Entrance Exam question as follows:
Which of the following algorithm has the higher bias?
- GMM
- GMM (identity covariance matrix)
- spectral clustering
- k-means
The answer mentioned is (4), but some search on google showed me maybe (1) and (2) is equal to (4). Why would k-means be the algorithm with the highest bias? (Can you please also provide references to valid material to study more?)