Isye 6501 Midterm 2 Intro Analytics Modeling Questions And Answers 2025 Updates Solutions

what is the objective function for a time series model {Ans: minimize prediction error}How do you choose t in LASSO {Ans: use the lasso approach with different values of t and see which gives the best trade off}What does k < 1 mean in a weibull distribution {Ans: modeling when failure rate decreases with time; worst things fail first (mechancial parts), the parts that are left are the better ones and take longer to fail}What is the objective function for hard classification {Ans: maximize the margin}what is forward selection {Ans: we select the best new factor and see if it's good enough (R^2, AIC, or p-value) add it to our model and fit the model with the current set of factors. Then at the end we remove factors that are lower than a certain threshold}what is a key difference between stepwise regresson and lasso regression {Ans: If the data is not scaled, the coefficients can have artificially different orders of magnitude, which means they'll have unbalanced effects on the lasso constraint.}