ISYE 6501 - Midterm 1 Exam – Questions And Answers What do descriptive questions ask? ✔️Ans - What happened? (e.g., which customers are most alike) What do predictive questions ask? ✔️Ans - What will happen? (e.g., what will Google's stock price be?) What do prescriptive questions ask? ✔️Ans - What action(s) would be best? (e.g., where to put traffic lights) What is a model? ✔️Ans - Real-life situation expressed as math.What do classifiers help you do? ✔️Ans - differentiate What is a soft classifier and when is it used? ✔️Ans - 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? ✔️Ans - 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? ✔️Ans - The vertical attribute is all that is needed.What is time-series data? ✔️Ans - The same data recorded over time often recorded at equal intervals What is quantitative data? ✔️Ans - Number with a meaning: higher means more, lower means less (e.g., age, sales, temperature, income) What is categorical data? ✔️Ans - 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?
- The average cost of a house in the United States every year since 1820 1 / 3
- The height of each professional basketball player in the NBA at the start of
- The contents of a person's Twitter feed
- The amount of money in a person's bank account ✔️Ans - B
- The 14th person's family size and car type
- The 14th person's family size
- As lambda drops towards zero
the season ✔️Ans - A Which of these is structured data?
What is structured data? ✔️Ans - Data that can be stores in a structured way What is unstructured data? ✔️Ans - 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?
C.The car type of each person ✔️Ans - A.A data point is all the information about one observation The farther the wrongly classified point is from the line ___ ✔️Ans - 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. ✔️Ans - 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. ✔️Ans
What can SVMs be used for ✔️Ans - to find a classifier with maximum seperation or margin between the two sets of points?When to use SVM? ✔️Ans - 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 ✔️Ans - What does this formula describe? 2 / 3
Total error ✔️Ans - What does this formula describe ?To maximize the distance between the two lines what do we need to minimize? ✔️Ans - m_j > 1 ✔️Ans - What value do we give for more costly errors Giving a bad loan is twice as costly as withholding a good loan? ✔️Ans - What does this mean in the context of giving a loan?m_j < 1 ✔️Ans - What value do we give for less costly errors?Why is it important to scale our data when using SVM? ✔️Ans - 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 ✔️Ans
- it means the corresponding attribute is probably not relevant
- / 3
What do kernel methods allow for in SVMs ✔️Ans - nonlinear classifiers What is the common range for scaled data? ✔️Ans - between 0 and 1 What is the formula for min-max scaling? ✔️Ans - find min and max for a factor what is common standardization and its formula? ✔️Ans - scaling to a normal distribution with a mean of 0 and standard deviation of 1.what is the formula for general scaling between b and a ✔️Ans - When do you use scaling? ✔️Ans - Data in a bounded range (e.g., neural networks, RGB values, SAT scores, batting averages) When do you use standardization? ✔️Ans - PCA or clustering