Coursera Machine Learning 第一周 引言(Introduction) quiz 習題答案

1.

A computer program is said to learn from experience E with

respect to some task T and some performance measure P if its

performance on T, as measured by P, improves with experience E.

Suppose we feed a learning algorithm a lot of historical weather

data, and have it learn to predict weather. What would be a

reasonable choice for P?

The probability of it correctly predicting a future date's weather.

The process of the algorithm examining a large amount of historical weather data.

None of these.

The weather prediction task.

第一題Answer:這是一道監督學習的題目，根據以往的天氣，預測将來的天氣，E為之前天氣的資料，P為測量的準确率，T為預測算法，故選B

2.

Suppose you are working on weather prediction, and use a

learning algorithm to predict tomorrow's temperature (in

degrees Centigrade/Fahrenheit).

Would you treat this as a classification or a regression problem?

Classification

Regression

第二題Answer:這是一道監督學習的題目，根據以往的天氣，預測将來的天氣，由于預測的溫度是連續的值，故為回歸問題，如為離散的值，則為分類問題，如預測第二天(多雲，晴，陰，雨)此為分類。故此題選擇回歸B。

3.

Suppose you are working on stock market prediction. You would like to predict whether or not a certain company will win a patent infringement lawsuit (by training on data of companies that had to defend against similar lawsuits). Would you treat this as a classification or a regression problem?

Regression

Classification

第三題Answer:這是一道監督學習的題目，根據以往股票資料預測公司勝訴的幾率，由于此題中公司隻有勝訴或者敗訴兩種情況，故屬于分類問題選擇B。

4.

Some of the problems below are best addressed using a supervised

learning algorithm, and the others with an unsupervised

learning algorithm. Which of the following would you apply

supervised learning to? (Select all that apply.) In each case, assume some appropriate

dataset is available for your algorithm to learn from.

Examine a large collection of emails that are known to be spam email, to discover if there are sub-types of spam mail.

Given historical data of children's ages and heights, predict children's height as a function of their age.

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".

第四題Answer:第一個根據垃圾郵件發現垃圾郵件的子類型，沒有給正确答案屬于分類，第四個搜集1000篇文章，沒有給文章的類型，以及應該怎麼分類，故屬于非監督學習。PS：界定監督學習與非監督學習，看給的資料是否有想要的正确答案即可選擇BC。

5. 

Which of these is a reasonable definition of machine learning?

Machine learning is the field of study that gives computers the ability to learn without being explicitly programmed.

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

Machine learning is the science of programming computers.

Machine learning learns from labeled data.

第五題Answer:機器學習是給計算機一種不需要明确程式指令可以自學習的能力選擇A。