Regression analysis

This is the simple notes for Students who studying basic Bio statistics.

1. REGRESSION ANALYSIS

2. INTRODUCTION Regression is Stepping Back or Going Back. The Term Regression was designed by Sir Franscis Galton Regression analysis is the most often applied technique of statistical analysis and modeling.

3. If two variables are involved, the variable that is the basis of the estimation, is conventionally called the independent variable and the variable whose value is to be estimated+ is called the dependent variable. The dependent variable is variously known as explained variables , predictand , response and endogenous variables . While the independent variable is known as explanatory , regressor and exogenous variable .

4. Definition The Regression Analysis is the measure of the average relationship between two or more variables in terms of the original units of the data. The regression technique is primarily used to : It is used in all those fields where two or more relative variables are having the tendency to go back to the average. It predicts the values of dependent variables from the value of independent variables.

5. Types of Regression Analysis There are 3 types regression analysis Simple and Multiple Linear and Non Linear Total and Partial

6. Simple and Multiple The regression analysis confined to the study of only two variables at a time is termed as Simple Regression . The regression analysis for studying more than two variables at a time known as Multiple Regression

7. Linear and Non Linear In Linear Regression, the regression is a straight line. On the other hand in on – Linear regression, the regression is not a straight line.

8. Total and Partial In total regression, all the important variables are considered. But in the case of partial regression one or more variables are considered but not all, thus excluding the influence of those not found relevant for a given purpose.

9. Methods of Studying Regressio n Graphic Method Scatter Diagram Algebraic Method Regression equations Regression c oefficient

10. Graphic Method Under this method the points are plotted on a graph paper representing various pairs of values of the concerned variables. These points give a picture of the scatter diagram with several points scattered around. A regression line may be drawn in between these points either by free hand or b a scale rule in such a way that the squares of the vertical or the horizandal .

11. Algebraic Method Under algebraic method, the equation of the line is derived by some suitable method. This equation can be of a straight line or of a parabola depending upon the scatter points and the suitability for the purpose in hand.

12. THANK YOU