INTRODUCTION TO SIMPLE REGRESSION LINEAR MODEL 

We are business consultant of the MINI MARKET company, based on various 
shops. The general director want create a new shop in Ferrara, but to individuate the 
typology and dimension, he ask us to undersand the relationship 
between the the sales volume and the size of the sales points.

#this is a simple example and we create our sample of data#
#the size of shops is expressed in Mq(100)
the annual sales is expressed in Euro (1000). 
before to develop a model, we want analyze the distribution of our data

#size = x 
#annual sales volumes = y #

#let's create our database#

x=c(3.7,3.6,3.8,5.6,1.3,2.2,3.3,4.1,3.2,4.5,5.2,4.6,3.8,3)
y=c(8.7,7.9,6.7,9.5,8.4,5.6,3.7,6.7,5.5,6.9,10.7,7.6,7.8,4.1)

#1. let's observe the data#
hist(x)
hist(y)
mean(x)
median(x)
mean(y)
median(y)

plot(x,y)