R Language

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# R Language - PowerPoint PPT Presentation

R Language. What is R? Variables in R Summary of data Box plot Histogram Using Help in R. What is R ?. R is a free, cross-platform, open-source statistical analysis language and program.  Many statistical functions are already built in. Variables. Numeric > a = 49 > sqrt(a)

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### R Language

What is R?

• Variables in R
• Summary of data
• Box plot
• Histogram
• Using Help in R
What is R ?
• R is a free, cross-platform, open-source statistical analysis language and program.
• Many statistical functions are already built in
Variables
• Numeric

> a = 49

> sqrt(a)

[1] 7

• String

> a = "The dog ate my homework"

> sub("dog","cat",a)

[1] "The cat ate my homework“

• Logical

> a = (1+1==3)

> a

[1] FALSE

vector: an ordered collection of data of the same type

> a = c(1,2,3)

To examine the contents of the variable a

>a

[1] 1 2 3

> a*2

[1] 2 4 6

> a[2]

[1] 2

list: an ordered collection of data of arbitrary types.

> d = list(name="john",age=28,married=F)

> d\$name

[1] "john“

> d\$age

[1] 28

Mean
• Dataset:

> x=c(0,4,15, 1, 6, 3, 20, 5, 8, 1, 3)

>y= 1:6

>y

[1] 1 2 3 4 5 6

• The Mean

> mean(x)

[1] 6

OR

> sum(x)/length(x)

[1] 6

Median
• Sort the dataset if it is not sorted

>sort(x)

[1] 0 1 1 3 3 4 5 6 8 15 20

• The Median

> median(x)

[1] 4

> median(y)

[1] 3.5

Quantiles
• Q1

> quantile(x,0.25)

25%

2

• Q3

> quantile(x,0.75)

75%

7

• Quantiles

> quantile(x,c(0,0.25,0.5,0.75,1))

0% 25% 50% 75% 100%

0 2 4 7 20

Five Number Summary

> summary(x)

Min. 1st Qu. Median Mean 3rd Qu. Max.

0 2 4 6 7 20

The Spread of the Data Set
• Range

> range(x)

[1] 0 20

• IQR

> IQR(x)

[1] 5

Boxplot
• Standard Boxplot

> boxplot(x,range=0)

• Modified Boxplot

> boxplot(x)

Histogram

> hist(x)

> hist(x,main=“Weight Gain”)

>hist(x , main=“Weight Gain”,xlab=“Weight Gain”, ylab =“Frequency”)

• Change the color

>hist(x , main=“Weight Gain”,xlab=“Weight Gain”, ylab =“Frequency”, col=“blue”)

> mydata

Age Income

1 10 0

2 25 35000

3 43 75000

4 32 55000

5 70 25000

6 19 20000

7 5 0

8 21 20000

9 35 60000

10 24 30000

How to use help in R?
• R has a very good help system built in.
• If you know which function you want help with simply use ?_______ with the function in the blank.
• Ex: ?hist.
• If you don’t know which function to use, then use help.search(“_______”).
• Ex: help.search(“histogram”).
Activity
• Using R language, Answer question 4 from the Tutorial.
• Export the resulted graphs.