UPDATED ISYE6501 Final EXAM QUESTIONS AND ANSWERS /ISYE 6501 FINAL EXAM LATEST UPDATE 2024

What do descriptive questions ask? - ANSWER-- What happened? (e.g., which customers are most alike) What do predictive questions ask? - ANSWER-- What will happen? (e.g., what will Google's stock price be?) What do prescriptive questions ask? - ANSWER-- What action(s) would be best? (e.g., where to put traffic lights) What is a model? - ANSWER-- Real-life situation expressed as math. What do classifiers help you do? - ANSWER-- differentiate What is a soft classifier and when is it used? - ANSWER-- In some cases, there won't be a line that separates all of the labeled examples. So we use a classifier that minimizes the number of mistakes. What does it mean when the classifier/decision boundary is almost parallel to the vertical x-axis? - ANSWER-- The horizontal attribute is all that is needed. What does it mean when the classifier/decision boundary is almost parallel to the horizontal y-axis? - ANSWER-- The vertical attribute is all that is needed. What is time-series data? - ANSWER-- The same data recorded over time often recorded at equal intervals What is quantitative data? - ANSWER-- Number with a meaning: higher means more, lower means less (e.g., age, sales, temperature, income) What is categorical data? - ANSWER-- Numbers w/o meaning (e.g., zip codes), non-numeric (e.g., hair color), binary data (e.g., male/female, yes/no, on/off) Which of these is time series data? A. The average cost of a house in the United States every year since 1820 B. The height of each professional basketball player in the NBA at the start of the season - ANSWER-- A Which of these is structured data? A. The contents of a person's Twitter feed B. The amount of money in a person's bank account - ANSWER-- B What is structured data? - ANSWER-- Data that can be stores in a structured way What is unstructured data? - ANSWER-- Data that is not easily described and stored (e.g., written text) A survey of 25 people recorded each person's family size and type of car. Which of these is a data point? A. The 14th person's family size and car type B. The 14th person's family size C.The car type of each person - ANSWER-- A. A data point is all the information about one observation The farther the wrongly classified point is from the line ___ - ANSWER-- The bigger the mistake we've made The term including the margin gets larger so the importance of a large margin out weights avoiding mistakes and classifying known data samples. - ANSWER-- As lambda gets larger That term also drops towards zero, so the importance of minimizing mistakes and classifying known data points outweighs having a large margin. - ANSWER-- As lambda drops towards zero What can SVMs be used for - ANSWER-- to find a classifier with maximum seperation or margin between the two sets of points? When to use SVM? - ANSWER-- If it's impossible to avoid classification errors, SVM can find a classifier that trades off reducing errors and enlarging the margin. Error for data point j - ANSWER-- What does this formula describe? Why is it important to scale our data when using SVM? - ANSWER-- We're looking to minimize the sum of the squares of the coefficients, but if our data has very different scales a small change in one could swamp a huge change in the other. what does it signify when a coefficient for a classifier is close to zero - ANSWER-- it means the corresponding attribute is probably not relevant What do kernel methods allow for in SVMs - ANSWER-- nonlinear classifiers What is the common range for scaled data? - ANSWER-- between 0 and 1 What is the formula for min-max scaling? - ANSWER-- find min and max for a factor