# Q15 Quiz Instruction

📗 The quizzes must be completed during the lectures. No Canvas submissions are required. The grades will be updated by the end of the week on Canvas. Alternative ways to get the points are listed below in the D15 sections.
📗 Please submit a regrade request if (i) you missed a few questions because you are late or have to leave during the lecture; (ii) you selected obviously incorrect answers by mistake (one or two of these shouldn't affect your grade): Link

# D4 Sharing Solutions on Piazza

📗 Use the sign-up sheet: Google Sheet. You can sign up and post anonymously (anonymous Piazza posts are not anonymous to instructors).



If your post satisfies the requirements (1), (2), (3), one of the course staff will "like" your post and you will receive 0.5 points for the post.
The past exams can be found on pages X1, X2, X3, X4, X5,

# D4 Discussion Topic

📗 Please create a follow-up discussion post on the Piazza (it is okay to post anonymously). No Canvas submissions are required. The grades will be updated at the end of the week on Canvas.



If your post satsifies the requirements (1), (2), you will receive 0.5 points for the post.

📗 Go to the K-means clustering demo Link and find an example in which the algorithm converges to a local minimum that is not a global minimum. Please also include the global minimum clustering for the same dataset. Share the two screenshots on Piazza.
📗 You should select "I'll Choose" for "How to pick the initial centroids?", then select a data set: please specify in the post which data set you used (e.g. mine is Gaussian Mixture).
📗 You can use the same one I gave during the lecture, but make sure you can replicate it.


Screenshot from K-Means Demo by Naftali Harris.