Regression Analysis Flashcards
What is regression?
Regression allows us to gain insights into the structure of the relationship between variables and provides measures of how well the data fits that relationship
What is a scatter plot?
-Displays the relationship between two continuous variables
-Makes it easy to spot outliers in data
-Visualises the strength and direction of correlation
What is the correlation coefficientq
A statistical measure that describes the strength and direction of the relationhip between two variables
What numbers are a small correlation
0.1-0.3 or -0.1-0.3
What is a moderate correlation
0.3-0.5 or -0.3-0.5
What is a strong correlation?
0.5-1.0 or -0.5-1
What is the process of regression analysis?
- Identify cause and effect
- Handle multiple independent variables
- Quantify the impact
- Test statistical significance
What is X
Independant variable (Cause)
What is Y
Dependant variable (Effect)
What is single-variable regression analysis?
Allows you to predict outcomes using one independent variable
Y = a +bX
-intercept (a) represents the Y value
-the slope (b) describes the relationship between Y and X by stating the ratio of the change in Y to change in X
Coefficients - b>0
As the independent variables increase, so does the dependent variable.
Coefficient - b=0
No relationship, meaning the variables are not correlated
Coefficient - b<0
A change in the independant variable will produce the oppoite effect in the dependant variable
What are the limiatations of ingle-variable regression?
In real life, more than one independent variable is needed to explain the variation in a dependant variable.
Process of multiple regression analysis
- Define problem
- Build hypotheses
- Collect data
- Operationalize variables
- Run multiple regression in SPSS/Excel
- Interpret results
