Biostats Exam 3 (Regression)

Regression

Predict an output

How does Regression differ from Correlation? (correlation)

quantifies the strength of the linear relationship

How does Regression differ from Correlation? (regression)

Expresses the relationship in the form of an equation.

Finding a linear regression line equation

y = mx + b

What is a requirement regarding the number of variables in linear regression?

Requires 2 or more scalar variables

What types of variables are involved in linear regression?

Dependent variable and one or more Independent variables

What type of relationship does linear regression assume between variables?

Linear relationship

What is the homoscedasticity assumption in linear regression?

The data must be homoscedastic

Homoskedasticity

the variance of the error term is constant

heteroskedastic

Graph gets wider the more time goes on

Linear Regression Output (R)

correlation of model output

R^2

coefficient of determination

Adjusted R2

independent variables and the sample size

Std. Err. of the Estimate

A measure of how accurately the model predicts the dependent variable

ANOVA tells us

the independent variables overall predict the dependent

Unstandard B

the unit change in the dependent per unit change in the independent

Beta

tells you how strongly this variable predicts the dependent

t & sig

if the variable was a significant predictor of the dependent