#BIOSTATISTICS 020
#DESCRIPTIVE STATISTICS:

#CALCULATIONS:
2+2
35/5
6*5
pi

#ASSIGNMENT:
var=78
var2=6*(7/9)
var3=(5+3)/(sqrt(pi))

#EVALUATION:
var
var2
var3

#INPUT DATA:

I1=read.table(file.choose())

I1 #EVALUATION OF I1

I2=read.table("iris.txt")
I2 #EVALUATION OF I2

#VARIABLE ASSIGNMENTS:
Iris=I2         
SL=Iris[,1]
SL=Iris$Sepal.Length

SW=Iris$Sepal.Width
PL=Iris$Petal.Length
PW=Iris$Petal.Width
Species=Iris[,5]

#EVALUATION:
Out=cbind(SL,SW,PL,PW,Species)
Out

#DESCRIPTIVE STATISTICS:

length(SL)
length(Iris$Sepal.Width)
length(Iris[,3])
length(PW)

n=length(SL)
n
SL[2]
SL[3]       #NOTE INDEX RANGE HERE!
Iris[3,1]

Xbar= (1/n)*sum(SL)
Xbar
mean(SL)

median(SL)

geom_meanSL = prod(SL)^(1/length(SL))
geom_meanSL

harm_meanSL = n/(sum(1/SL))
harm_meanSL

#VARIANCE:
var(SL)       #SAMPLE VARIANCE
Population_VarSL=((n-1)/n)*var(SL)
Population_VarSL  #POPULATION VARIANCE

#LINEAR TRANSFORMATION OF MEAN AND VARIANCE
b=32
c=1.8

SLt=c*SL+b
mean(SLt)
var(SLt)