Exam (elaborations)
ISYE 6501 Final Questions and Answers.
- Course
- Institution
ISYE 6501 Final Questions and Answers.
[Show more]
Seller
Follow
Content preview
ISYE 6501 Final Questionsand Answers
Denning [Date] [Course title]
, Factor Based Models - Correct Answers:s :classification, clustering, regression. Implicitly assumed that
we have a lot of factors in the final model
Why limit number of factors in a model? 2 reasons - Correct Answers:s :overfitting: when # of factors is
close to or larger than # of data points. Model may fit too closely to random effects
simplicity: simple models are usually better
Classical variable selection approaches - Correct Answers:s :1. Forward selection
2. Backwards elimination
3. Stepwise regression
greedy algorithms
Backward elimination - Correct Answers:s :variable selection; classical
Opposite of forward selection. Start with model with all factors, at each step find worst factor and
remove from model. Continue until no more to add, # of factor threshold is satisfied. Remove factors at
the end that were not good enough
Forward selection - Correct Answers:s :variable selection; classical
Start with model with no factors, at each step find best new factor to add. Continue until none bad
enough to remove, # of factor threshold is satisfied. Remove factors at the end that were not good
enough
Stepwise regression - Correct Answers:s :variable selection; classical
Combination of forward selection and backwards elimination. Start with all or no factors. Each step
remove/add a factor. As it continues, after adding in new factor we eliminate right away any factors that
may be good. Helps model adjust when new factors are added, goodness values change
Ways of determining if factors are good enough in variable selection - Correct Answers:s :p-value,
Rsquared, AIC, BIC
Greedy algorithm - Correct Answers:s :At each step, it does the one thing that looks best
without taking future options into consideration. Good for initial analysis
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller NETEXPERT. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $12.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
79223 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now