# Lecture 14 - Correlation and Multiple Regression Theory Flashcards

What are the three types of multiple regression?

simultaneous

stepwise

hierarchical

what does regression allow us to do?

to predict Y based on knowledge of X

What does the criterion mean?

It can be used to refer to the dependent variable

What measure of association do we use when variable 1 and 2 are both interval or ratio level data (e.g. height and agE)

Pearsons

what measure of association do we use when variable one and 2 are both ordinal (ranked)

Spearman’s Rho

OR

Kendall’s Tau

What measure of association do we use when both variables are a ‘true dichotomy’ (only two options), e.g. gender and pass/fail

Phi

What measure of association do we use when one variable is a true dichotomy (e.g. gender) and one variable is interval/ratio level data (e.g. weight

Point-Biserial

In a venn diagram what does the size of the circle represent?

The variance of that variable. So the bigger the more variable that data is.

What do we use a partial correlation for?

To tell us about the relationship between 2 variables, once all other variables have been removed

How does a partial correlation work?

it measures the strength of dependence between two variables, which is not accounted for by the way in which they both change in response to variations in a selected subset of other variables

What is multiple regression for?

It lets us learn about the relationship between several IV’s (predictors) and one dependent variable (the crierion)

such as, how does size, number of bedrooms, income of area relate to the selling price of a house?

how does age, gender, stress etc relate to depression?

What is the objective of multiple regression

to find the model that best fits the data whilst minimising overall prediction error

What happens when there is one predictor in a regression?

that’s when its linear regression - the line must be a straight line since there is only the one IV and the DV

In a regression equation, what is B0

the intercept (where the line meets the y axis)

In a regression equation, what is B1

the slope of the regression line