Homework1 : Overview of R Programming Language

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What is R?

·According to Wikipedia, R is
-A free software programming language
-A software environment for statistical computing and graphics -An implementation of the S programming language combined with lexical scoping semantics inspired by Scheme
-A GNU project

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Why R?

·Free (as Free Speech and Free Beer) and open source
·Inherits the power and flexibility of the S language
·Runs on all major operating systems, including Windows, Mac, Unix, and Linux, etc.
·Huge and vibrant user community
·Platform of choice for cutting-edge statistical methodology
·State-of-the-art developmental environment, Rstudio
·The most widely used tool for the new field of data science

Here is a good summary.

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Now’s a great time to learn R

·Microsoft, the largest software company on earth, just bought Revolution Analytics, the most important R-based company
·R-related jobs (“data scientists”) experienced an explosive increase since 2011

·R has become the language of choice of major businesses, governmental agencies, and NGOs, including Bank of America, Facebook, FDA, Ford, Google, Microsoft, .

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Some examples with R

x1 <- rnorm(100)
summary(x1)

##      Min.   1st Qu.    Median      Mean   3rd Qu.      Max. 
## -1.775000 -0.567400 -0.037080 -0.004672  0.552100  1.757000

hist(x1, main =paste("Normal distribution with 100 observations"))

x2 <- rnorm(100000)
summary(x2)

##      Min.   1st Qu.    Median      Mean   3rd Qu.      Max. 
## -4.778000 -0.672100  0.001816  0.001635  0.676000  4.016000

hist(x2, main = paste("Nomral distribution with 100,000 observations"))