What happened? (e.g., which customers are most alike)
What do predictive questions ask?
What will happen? (e.g., what will Google's stock price be?)
What do prescriptive questions ask?
What action(s) would be best? (e.g., where to put traffic lights)
What is a model?
Real-life situation expressed as math.
What do classifiers help you do?
differentiate
,What is a soft classifier and when is it used?
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?
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?
The vertical attribute is all that is needed.
What is time-series data?
The same data recorded over time often recorded at equal intervals
What is quantitative data?
Number with a meaning: higher means more, lower means less (e.g., age, sales, temperature, income)
,What is categorical data?
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
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
B
What is structured data?
Data that can be stores in a structured way
, What is unstructured data?
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
A.
A data point is all the information about one observation
The farther the wrongly classified point is from the line ___
The bigger the mistake we've made