Embed Size (px)
Citation preview
Introduction to R project
Marek Majdan
Training in essential biostatistics for Public Health Professionals in BiH, Marek Majdan, PhD; [email protected]
R project
• Statistical computing environment and software
• Absolutely free• Updated by statisticians• Very powerfull • Basically unlimited capability
Training in essential biostatistics for Public Health Professionals in BiH, Marek Majdan, PhD; [email protected]
R project - principle
Editor R Engine
Numerical output
Graphical Output
SCRIPT
Training in essential biostatistics for Public Health Professionals in BiH, Marek Majdan, PhD; [email protected]
Script example
library (RODBC)library(foreign)library(Hmisc)library(Design)library(graphics)
barb <- sqlFetch(odbcConnectExcel("d:/barb_data_new.xls"),sqtable = "data", na.strings = "NA", as.is = T)
summary(barb)describe(barb)describe(barb$barb_group)
##normality tests
shapiro.test(barb$AGE_CORRECTED)
Training in essential biostatistics for Public Health Professionals in BiH, Marek Majdan, PhD; [email protected]
Packages
• Base package• Contributed packages
- specific functions written for specific purposes- not included in the base package- can be installed any time
Training in essential biostatistics for Public Health Professionals in BiH, Marek Majdan, PhD; [email protected]
R EDITOR
NUMERICAL OUTPUT
GRAPHICAL OUTPUT
Training in essential biostatistics for Public Health Professionals in BiH, Marek Majdan, PhD; [email protected]
Installing R
Training in essential biostatistics for Public Health Professionals in BiH, Marek Majdan, PhD; [email protected]
Installing R
Training in essential biostatistics for Public Health Professionals in BiH, Marek Majdan, PhD; [email protected]
Installing Packages
1.
2.3.
Training in essential biostatistics for Public Health Professionals in BiH, Marek Majdan, PhD; [email protected]
Writing scripts
• Every package contains ‘functions’ for performing various operations with data
• Every function has a specific form and arguments needed
• Every function has a specific output• An algorithm of functions to perform a specific
sequence of actions is a script
Training in essential biostatistics for Public Health Professionals in BiH, Marek Majdan, PhD; [email protected]
Example I.
• Function: library• To load a specific package• Form: library (name of package)
library (Epicalc)library (Hmisc)
Training in essential biostatistics for Public Health Professionals in BiH, Marek Majdan, PhD; [email protected]
Example II.
• Function: plot• To plot a graph• Simple form: plot(x)• Complex form with a number of additional
arguments:plot(x <- sort(rnorm(47)), type = "s", main = "plot(x, type = \"s\")") points(x, cex = .5, col = "dark red")
Training in essential biostatistics for Public Health Professionals in BiH, Marek Majdan, PhD; [email protected]
Important notes
• Case sensitivity
Plot ≠ plot ≠ PLOT
• Avoid using punctuation and spaces in names of databases or variables (e.g. use ‘age_category’ instead ‘Age category’)
Training in essential biostatistics for Public Health Professionals in BiH, Marek Majdan, PhD; [email protected]
Importing data to R from Excel
• Package: RODBC• Function: X=sqlFetch(odbcConnectExcel(“Y"),sqtable = “Z", na.strings = "NA", as.is = T)
X=name of database in R after importingY=path to excel file on diskZ=name of excel sheet
Training in essential biostatistics for Public Health Professionals in BiH, Marek Majdan, PhD; [email protected]
R commander
• Graphical user interface (GUI)• Makes basic statistical computations simple
but puts certain restrictions on R• Installing R commander: install package
‘Rcmdr’ using the standard package installing procedure
• Function: library(Rcmdr) to start R commander
Training in essential biostatistics for Public Health Professionals in BiH, Marek Majdan, PhD; [email protected]
R commander
Training in essential biostatistics for Public Health Professionals in BiH, Marek Majdan, PhD; [email protected]
