# Single Regression Analysis

If Y is one and X is one, the Regression Analysis is called "single regression analysis"

If X variables are more than two, it is called " Multi-Regression Analysis ".

## Formulation

By regression analysis, we can study the number of A and B. And we can study the relation between Y and X and the .

Least square is the famous way to get the formulation.

## How to understand the conclusion

### Analysis of Slope and Intercept A is called the slope. B is caaled the the intercept.

We study the relation between X and Y as the set of A and B.

In the analysis of energy and costs, B means the bottom line. The way to reduce A and B is the efficient improvement.

### Correlation Coefficient

We evaluate fitting with correlation coefficient. Coefficient of determination is square of correlation coefficient. And coefficient of determination is often expressed with percentage.

## For the case Y is Probability Data  If Y is the probability data, general regression analysis does not work well. The regeression line does not show the character of probability data. The straight is not good.

By the change, log( y / (1-y))
as the new y and we use it for regression analysis, we may get a good output.

If Y is 0 or 1, for example, we should use 0.0000000001 or 0.99999999999 as the Y. The change may work well.

If you know the change, it is easier to learn Logistic Regression Analysis .

NEXT   Regression Analysis for Curve 