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> # Sample Session
>
> # This is a comment
>
> 2 # print a number
[1] 2
> 2+3 # perform a simple calculation
[1] 5
> log(2)
[1] 0.6931472
>
> x <- 2 # store an object
> x # print this object
[1] 2
> (x <- 3) # store and print an object
[1] 3
>
> x <- "Hello" # store a string object
> x
[1] "Hello"
>
> Height <- c(168, 177, 177, 177, 178, 172, 165, 171, 178, 170) #store a vector
> Height # print the vector
[1] 168 177 177 177 178 172 165 171 178 170
>
> Height[2] # Print the second component
[1] 177
> Height[2:5] # Print the second, the 3rd, the 4th and 5th component
[1] 177 177 177 178
>
> (obs <- 1:10) # Define a vector as a sequence (1 to 10)
[1] 1 2 3 4 5 6 7 8 9 10
>
> Weight <- c(88, 72, 85, 52, 71, 69, 61, 61, 51, 75)
>
> BMI <- Weight/((Height/100)^2) # Performs a simple calculation using vectors
> BMI
[1] 31.17914 22.98190 27.13141 16.59804 22.40879 23.32342 22.40588 20.86112
[9] 16.09645 25.95156
>
> length(Height)
[1] 10
> mean(Height) # Compute the sample mean
[1] 173.3
> var(Height)
[1] 22.23333
>
> M <- cbind(obs,Height,Weight,BMI) # Create a matrix
> typeof(M) # Give the type of the matrix
[1] "double"
> class(M) # Give the class of an object
[1] "matrix"
> is.matrix(M) # Check if M is a matrix
[1] TRUE
> is.vector(M) # M is not a vector
[1] FALSE
> dim(M) # Dimensions of a vector
[1] 10 4
>
> plot(Height,Weight,ylab="Weight",xlab="Height",main="Corpulence")
>
>
> mydat <- data.frame(M) # Creates a dataframe
> names(mydat) # Give the names of each variable
[1] "obs" "Height" "Weight" "BMI"
> str(mydat) # give the structure of your data
'data.frame': 10 obs. of 4 variables:
$ obs : num 1 2 3 4 5 6 7 8 9 10
$ Height: num 168 177 177 177 178 172 165 171 178 170
$ Weight: num 88 72 85 52 71 69 61 61 51 75
$ BMI : num 31.2 23 27.1 16.6 22.4 ...
>
> View(mydat) # Look at your data
>
> summary(mydat) # Descriptive Statistics
obs Height Weight BMI
Min. : 1.00 Min. :165.0 Min. :51.00 Min. :16.10
1st Qu.: 3.25 1st Qu.:170.2 1st Qu.:61.00 1st Qu.:21.25
Median : 5.50 Median :174.5 Median :70.00 Median :22.70
Mean : 5.50 Mean :173.3 Mean :68.50 Mean :22.89
3rd Qu.: 7.75 3rd Qu.:177.0 3rd Qu.:74.25 3rd Qu.:25.29
Max. :10.00 Max. :178.0 Max. :88.00 Max. :31.18
>
