In the last chapter we saw how to describe the distribution of a single variable in a sample. However, in most cases, studies require to describe several variables that are often related.

Problems of Linear Regression

Exercise 1 Give some examples of: Non related variables. Variables that are increasingly related. Variables that are decreasingly related. Solution The daily averge temperature and the daily number of births in a city.

Problems of Non Linear Regression

Exercise 1 A dietary center is testing a new diet in sample of 12 persons. The data below are the number of days of diet and the weight loss (in kg) until them for every person.