ISYE 6414 REGRESSION MIDTERM 1 REAL EXAM 2023/2024

ISYE 6414 REGRESSION MIDTERM 1 REAL EXAM 2023/2024 What are the variables in regression? -CORRECT ANSWER1. Response (dependent) variable - one particular variable that we are interested in understanding or modelling, such as sales of a particular product. 2. Predicting or Explanatory (independent) variable - set of other variables that we think might be useful in predicting or modelling the response variable (like the price of a product) Which regression variable is a Random variable? -CORRECT ANSWER-- Response Variable - It varies with changes in the predictor along with other random changes Which regression variable is a Fixed variable? -CORRECT ANSWER-- Predicting Variable - It does not change with the response but it is set fixed before the response is measured. What are the objectives in regression analysis? -CORRECT ANSWER-- 1. Prediction - of the response variable 2. Modelling - the relationship between the response variable and the explanatory variables 3. Testing - hypotheses of association relationships. What are the given assumptions when building a linear regression model? - CORRECT ANSWER-- 1. Linearity/Mean Zero Assumption - it cannot be true that for certain subgroups in the population, the model is consistently too low, while for others, it's consistently too high. 2. Constant Variance Assumption - means that it cannot be true that the model is more accurate for some parts of the population, and less accurate for other parts of the populations. 3. Independence Assumption are independent random variables - it cannot be true knowing that the model under-predicts y for one particular case tells you anything or all about what it does for any other case. (her language) 4. Normally distributed. What is the value that is being optimized towards in a linear regression problem? - CORRECT ANSWER-- Minimizing the sum of squared errors