Basics of Regression Analysis
Regression
A measure of
relation between the mean value of one variable (e.g. output) and corresponding
values of other values (e.g. time and cost)
Uses
- Association
(fundamental of regression). If there is association between variables then we
go for regression analysis
- Prediction
(predict one variable by knowing other)
- Estimation
(parameter estimation)
Variables
involve liner regression
·
Y
axis dependent variables
·
X
axis independent variables (non random variables, using X to predict Y variable,
X is in researcher hand)
Example:
- Y is regressed on X
(Classical regression model)
- Blood pressure is regressed on age
- Dependent is
regressed on independent
·
Assumptions (LINE)
- Linearity (Straight line, Regression line)
- Independence (For X1 the value of Y1 is not dependent on Y2)
- For any given value X a set of Y value is normally distributed
- Equal
variances