** The Exercise**

The following table represents blood pressure y*i* in terms of age x*i* for a sample of men.

**1.** Represent a scatter plot of points M*i*(x*i*;y*i*) in
a perpendicular coordinate system with origin o'
(30;11) and a scale of 1 cm for every 5 years on the axis of abscissa
and 2 cm on the axis of ordinates.

**2**. **a)** Determine the coordinates of the centroid G of the **scatter plot**.

** b)** Represent the point G in the previous coordinate system.

**3.** Find the equation of the least squares regression line: y=ax+b, a and b are given rounded to 10^{-2}.^{ }

**4.** Plot this line in the previous coordinate system.

**5.** A man is 70 years old and his blood pressure is 15.2, is this reasonable according to this modification? Explain.

**Definition**

A **scatterplot **is a graph displaying the relationship between two variables. It is commonly used in data visualization to help identify patterns, trends, and correlations between two variables. In a scatterplot, each observation or data point is represented as a dot, and the position of the dot on the graph is determined by the values of the two variables being plotted.

The horizontal axis represents one variable, while the vertical axis represents the other variable. The position of each dot on the graph indicates the values of the two variables for that observation. A scatterplot can be used to identify relationships between the two variables, such as whether they are positively or negatively correlated or whether there is no relationship between them. It can also be used to identify outliers or unusual data points.

In general, a scatterplot is a useful tool for visually exploring data and identifying patterns and relationships that may not be immediately apparent from looking at the raw data alone.