Two Variable Statistics
Two variables x and y are functionally related when the value of the second variable can be calculated when the value of the first is known.
If a stone is dropped, the formula that allows us to accurately calculate the height if it is a function of elapsed time is:
h = ½ g t².
Two variables x and y are related statistically when the value of the second variable can be approximately estimated when the first is known.
Income and expenses for a family.
Production and sales for a factory.
Advertising expenses and profits for a corporate enterprise.
If each pair of values is represented as the coordinates of a point, the set of all points on a graph is called a scatter plot or a scatter diagram.
A line can be drawn on a scatter plot which best represents the trend of the points. This line is called a regression line.
The scores of 12 students in their Mathematics and Physics classes are: