Book Image

Data Science Using Python and R

By : Chantal D. Larose, Daniel T. Larose
Book Image

Data Science Using Python and R

By: Chantal D. Larose, Daniel T. Larose

Overview of this book

Data science is hot. Bloomberg named a data scientist as the ‘hottest job in America’. Python and R are the top two open-source data science tools using which you can produce hands-on solutions to real-world business problems, using state-of-the-art techniques. Each chapter in the book presents step-by-step instructions and walkthroughs for solving data science problems using Python and R. You’ll learn how to prepare data, perform exploratory data analysis, and prepare to model the data. As you progress, you’ll explore what are decision trees and how to use them. You’ll also learn about model evaluation, misclassification costs, naïve Bayes classification, and neural networks. The later chapters provide comprehensive information about clustering, regression modeling, dimension reduction, and association rules mining. The book also throws light on exciting new topics, such as random forests and general linear models. The book emphasizes data-driven error costs to enhance profitability, which avoids the common pitfalls that may cost a company millions of dollars. By the end of this book, you’ll have enough knowledge and confidence to start providing solutions to data science problems using R and Python.
Table of Contents (20 chapters)
Free Chapter
1
ABOUT THE AUTHORS
17
INDEX
18
END USER LICENSE AGREEMENT

PART 3: SUMMARIZATION 2: MEASURES OF CENTER, VARIABILITY, AND POSITION

  • The summation notationx means to add up all the data values x. The sample size is n and the population size is N.
  • Measures of center indicate where on the number line the central part of the data is located. The measures of center we will learn are the mean, the median, the mode, and the midrange.
    • The mean is the arithmetic average of a data set. To calculate the mean, add up the values and divide by the number of values. The mean income from Table A.1 is:
      equation38,000+32,000++32,20010=325,40010=$32,540--
    • The sample mean is the arithmetic average of a sample and is denoted imagesx¯--x‐bar”).
    • The population mean is the arithmetic average of a population and is denoted μ (“myu,” the Greek letter for m).
    • The median is the middle data value, when there is an odd number of data values and the data have been sorted into ascending order. If there is an even number, the median...