吴恩达机器学习笔记系列（一）——第一周练习题

一、review questions

1、第 1 个问题

A computer program is said to learn from experience E withrespect to some task T and some performance measure P if itsperformance on T, as measured by P, improves with experience E.Suppose we feed a learning algorithm a lot of historical weatherdata, and have it learn to predict weather. What would be areasonable choice for P?

• The probability of it correctly predicting a future date’s weather.
• The weather prediction task.
• None of these.
• The process of the algorithm examining a large amount of historical weather data.

2、第 2 个问题

Suppose you are working on weather prediction, and your weatherstation makes one of three predictions for each day’s weather:Sunny, Cloudy or Rainy. You’d like to use a learning algorithmto predict tomorrow’s weather.Would you treat this as a classification or a regression problem?

• Regression
• Classification

3、第 3 个问题

Suppose you are working on stock market prediction, and you would like to predict the price of a particular stock tomorrow(measured in dollars). You want to use a learning algorithm for this.Would you treat this as a classification or a regression problem?

• Regression
• Classification

4、第 4 个问题

Some of the problems below are best addressed using a supervisedlearning algorithm, and the others with an unsupervisedlearning algorithm. Which of the following would you applysupervised learning to? (Select all that apply.) In each case, assume some appropriatedataset is available for your algorithm to learn from.

• Given 50 articles written by male authors, and 50 articles written by female authors, learn to predict the gender of a new manuscript’s author (when the identity of this author is unknown).
• Take a collection of 1000 essays written on the US Economy, and find a way to automatically group these essays into a small number of groups of essays that are somehow “similar” or “related”.
• Given historical data of children’s ages and heights, predict children’s height as a function of their age.
• Examine a large collection of emails that are known to be spam email, to discover if there are sub-types of spam mail.

5、第 5 个问题

Which of these is a reasonable definition of machine learning?

Machine learning is the field of allowing robots to act intelligently.

• Machine learning is the field of study that gives computers the ability to learn without being explicitly programmed.
• Machine learning is the science of programming computers.
• Machine learning learns from labeled data.