Introduction to Statistical Analysis Using R

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Introduction to Statistical Analysis Using R

• Nick, Caroline, Tanya

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What is R?

• R is a programming language for data analysis and
  graphics
• All information about R is found on
  http//www.R-project.org
• R system contains two major components
• Base system contains the R language software
  and the high priority add-on packages listed on
  pg.3
• User contributed add-on packages

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Who uses R?

• All scientists especially those working in
  developing countries
• It allows universal free access to state of the
  art tools for statistical data analysis
• Most widely used for teaching undergraduates and
  graduates statistics b/c the students can use it
  free of cost

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Installing RBase System

1. Go to http//CRAN.R-project.org
2. Choose your computer from the list (Linux, MacOS
   X, or Windows)
3. Click on Base (Base or Contrib)
4. Click on R-2.6.1-win32.exe
5. Save R

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Getting Started

• Changing prompt - pg.3
• Example using R as a pocket calculator pg.3
• Storing vs. Printing
• R is not space sensitive, but it is case
  sensitive

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Getting Help in R

• The Help system is a collection of manual pages
  describing each function and data set that comes
  with R
• Help/manual page is shown when the name of the
  function we would like to get help for is
  supplied to the help function
• Ex. help(mean) or help(mean) or ?mean

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Installing add-on packages

• All packages are available on http//CRAN.R-proje
  ct.org/src/contrib/PACKAGES.html
• Pick package from list and download
• To install add-on package
• 1. install.packages(package name)
• 2. library(package name)

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Forbes2000 Example

• Go to http//CRAN.R-project.org/src/contrib/PACKAG
  ES.html and select HSAUR from the list
• Choose what pertains to your computer ex. Windows
  binary HSAUR 1.2-1.zip
• Save to desktop
• Find Forbes2000 list in rawdata folder
• Install in R
• install.package(HSAUR)
• library(HSAUR)

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Working with Data Sets Ex. Forbes 2000 list

• Vector elementary structure for data handling
  in R set of simple elements, all being objects
  of the same class
• Ex. First 3 companies in Forbes -
  Forbes2000,"name"13
• Variable names headings
• names(Forbes2000)
• Finding structures of data set useful for large
  data sets
• str(Forbes2000)
• Dimensions
• dim(Forbes2000)
• nrow(Forbes2000)
• ncol(Forbes2000)

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Simple Summary Statistics

• Mean mean(Forbes2000 ,sales)
• Median median(Forbes2000 ,assets)
• Range range(Forbes2000 ,sales)

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Importing Data Not Part of a Package

• When is this used?
• Most data sets are not part of a down-loadable
  package
• Most people need to import their own data sets
  into R
• Example Airport data (download to Desktop)
• In R
• File ? Change Dir ? Desktop ? OK
• name given lt - read.table (airport.csv, header
  TRUE, sep ,, row.names 1

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Making a Graph

• Graph of Rank of airport vs. Shop
• Plot (Rank Shop, data name given, pch O)

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Homework

• Change Prompt gt to Rgt
• Import Airport Data Set from Excel
• Print data set in R
• Find the Dimensions, the number of Columns, and
  the number of Rows in the data set
• Find structure of data set
• Find median of category Shop
• Find mean of Domestic

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Contact info

• Tanya tgranch_at_luc.edu
• Caroline cweber4_at_luc.edu
• Nick ngundru_at_luc.edu