ISYE 6501 Midterm 2 Part 1 Exam With 100% Verified Answers Guaranteed Success.

greedy algorithm - correct answer at each step, the algorithm does the thing that looks best without taking future options into consideration; more classical variable selection methods - correct answer stepwise - (forward, backward, combination) lasso elastic net available metrics for variable selection criteria - correct answer p-value r2 AIC / BIC lasso - correct answer Giving regression a budget to use on coefficients which it uses on most important coefficients Have to scale first elastic net - correct answer constrain combination of absolute value of coefficients and their squares have to scale first Note: if absolute value is removed, ridge regression (to be covered later) prediction error - correct answer function of bias and variance model complexity on x axis error on y axis bias squared decreasing, variance increasing, prediction error concave curve with inflection point where (ish) bias squared = variance design of experiment - correct answer used as a means to quickly and efficiently get a subset of data Ex: polls, which similar products a retailer should display -keep in mind comparison / control and blocking blocking factor - correct answer something that could create variance in DOE A/B Testing - correct answer experiment design to test two alternatives; binomial data used to answer (with hypothesis test) which is better choice Experiment can be run n times or until results are significant A/B testing requirements - correct answer Quick collection of a lot of data Data must be representative Data collection size must be small compared to total size of use case A/B testing limitations - correct answer Does not address: Several alternatives, Learning as you go, Combination of factors factorial design - correct answer experiment design with more than two alternatives, but a small enough set of scenarios to test all testing combinations ANOVA determines importance of each factor fractional factorial design - correct answer experiment design with too many possible scenarios to test comprehensively where a subset of scenarios is tested independent factorial design - correct answer experiment design where factors are assumed to be independent; a subset of combinations of choices is tested, and regression is used to estimate effect of each choice; each factor gets a categorical variable Note that interaction terms are likely necessary; ex: font color and background color exploration v exploitation - correct answer more information v immediate value -- with regards to DOE multi armed bandit approach - correct answer testing k alternatives & starting with no information; run test and update information about probabilities of each being the best, assign new test Exploration, but since more likely to pick the best one, also exploitation memoryless property - correct answer it doesn't matter what happened in the past, all that matters is where we are now (exponential and poisson) balking - correct answer person thinks the wait is too long and leaves without completing transaction (checking out, talking to customer service rep on the phone, etc) Bernoulli Distribution - correct answer discrete distribution having two possible outcomes in which ("success") occurs with probability p and ("failure") occurs with probability (1-p); similar to flipping a coin but not constrained to 50/50 Binomial Distribution - correct answer Probability of getting x successes out of n independent identically distributed Bernoulli(p) trials Geometric Distribution - correct answer Probability of having x Bernoulli(p) failures until first success (or, x Bernoulli(1-p) successes until first failure)