CS 451 Quiz 24
Recommender systems and collaborative filtering
* Required
Email address
*
Your email
According to Andrew Ng, recommender systems
*
receive much attention in academia but are not widely used in industry
receive relatively little attention in academia, but are widely used in industry
Suppose user j has watched movie i and rated it 4 out of 5. Which of the following describes this scenario?
*
r(i, j) = 0 and y(i, j) = 4
r(i, j) = 1 and y(i, j) = 4
r(i, j) = 4 and y(i, j) = undefined
r(i, j) = 4 and y(i, j) = 5
To learn the movie ratings for user j, we can use
*
linear regression over all movies i
linear regression over all movies i for which r(i, j) = 1
logistic regression over all movies i
logistic regression over all movies i for which r(i, j) = 1
Collaborative filtering is an algorithm for
*
classification
clustering
density estimation
feature learning
One way to implement collaborative filtering is to alternate estimating theta's from x's, and x's from theta's. Which of the following algorithms operates in a similar way?
*
Knearest neighbors
Kmeans
PCA
Instead of alternating the two estimation problems, we can estimate x's and theta's jointly in a single minimization problem.
*
True
False
Why do we initialize x's and theta's to small random values?
*
This step is optional. Initializing to all 0's would work just as well.
Random initialization is always necessary when using gradient descent
This ensures that x(i) != theta(j) for any i, j
For symmetry breaking, so the algorithm can learn features that are different from each other
In collaborative filtering we don't need to include "bias" features x(0) = 1 and theta(0) = 1
*
True
False
Which of the following is NOT one of movie titles used as examples?
*
Romance forever
Swords vs. karate
Hot wheels of fire
Cute puppies of love
I'd rather not get a free point on this quiz.
*
True
False
HW 5 teams [not graded]
*
Please enter one of "working with [your partners name]", "working alone", or "still looking for a partner"
Your answer
Submit
Never submit passwords through Google Forms.
This content is neither created nor endorsed by Google.
Report Abuse

Terms of Service

Additional Terms
Forms