###Simple Linear Regression Model using R
###UNIFE 
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###Mini V. Ottobre-2019

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IN CLASS LAB:
Please, download the database called “eating” from the course’s website
We want to investigate the causal linear relationship between the alcohol consumption and the sugar consumption. 
0. Prepare the dataset and describe the variables of interest
1. Visualize the relationship (the scatter plot between x and y)
2. Identify the estimated model and writ up the equation you find: interpret the coefficients
3. Show the model on a graph
4. Prediction: the expected Y values given a X value equals 32
5. Assess and comment the model’s goodness of fit
6. Perform the graphical analysis of Linear Regression Model’s assumptions
7. Evaluate the possibility to make inference: does the linear relationship exist within the population? (assume a confidence level equals to 95%)