Common Stats Functions

Descriptive

# mean ()
# sd()
# cor()
# summary()

Inferential

Processing/cleaning Data

# length() find out how many values are there
# str()
# edit() you can create a data frame and use this function to add data 
# fix() you can edit your data frame 
# rnorm()
X <- rnorm(5, mean = 20, sd = 3.5)
# round()
Y <- round(X, digits = 2)
print(Y)

## [1] 19.48 15.42 24.33 24.08 19.40

# table () pass in any two variables for rows and columns 
# attach()
# dettach()
# with() good function to refer variables in different dataset 
with(mtcars, {
  print(summary(mpg))
  plot(mpg, disp)
  plot(mpg,wt)
})

##    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
##   10.40   15.43   19.20   20.09   22.80   33.90

# the limitation for with function is that variables created only exist in the brackets
# you can use special opprater <<- to have the variable exist outside of the brackets
# read.table('Studentgrades.cvs;, header= T, row.names ="studentID", sep = ")
# read.csv()
  # help(read.table)

More Processing Data

# length()
# dim()
# str()
# class()
# mode() determines how an object is stored
# names() give the names of components in an object
# c()
# cbind(object1, object2) combines two objectS as colomns  
# rbind() combines two objects as rows 
# object print an object 
# head()
# tail()
# ls()
# rm()
# newobject () <- edit(object) 
# fix()

Charts

# plot(x, y)
  # plot(dose, drugA, type= "b") this means both lines and dots should be ploted.
# hist()
# boxplot()
# par() is used for specify graphic parameters, means values the same unless changed, for the entire dataset
    # par(lty = 2, pach = 17) line type and solid triangle
    # pch = symbols for plotting 
    # cex = sybol size, number of scaled, default = 1, 1.5 is 50% larger, 0.5 is 50% smaller, 
    # lty = specifies the line type 
    # lwd = line width 1 is default. 
# rgb(1,1,1) create colors based on red-green-blue values.  
# rainbow(), heat.colors(), terrain.color(), topo.colors(), and cm.colors()
  # rainbow(10) give you 10 continuous rainbow colors
# abline(lm(mpg~wt))
# title("Regression of MPG on Weight")
# pdf("Title.pdf")
 # blocks of codes 
# dev.off() 

Others

# c() combine variables/objects 
# detach() Detach data 
# getwd() get working directory 
# setwd() set working directory 
# q() this ends the function and let you quit 
# demo() enter this in the command line without any parameters  
# data() shows you the dataset 
# help.start() general help, will show you a windows in doc section 
# help('foo') or ? foo shows you help on function foo (quotation marks are optional)
# help.search('foo') will search strings of "foo" in help system 
# example() shows you an example of function
# RsiteSearch('Foo") this will search things on R site 
# vigette() you need to have quotation marks for it to run 
# ls() will list all the variables in your workspace
# rm() remove any variable you want 
# :: used to specify what package and what variables/function that you want
# history()
# search() tell you which packages are installed and ready to use