What is a linear regression model?
The relationship between two values and how their changes correspond to one another
What is the independent variable + secondary name?
It is the variable that causes change in the response variable (controlled)
It is also called the PREDICTOR variable
What is the dependent variable + secondary name?
It is the variable that is measured in studies. (uncontrolled)
It is also called the RESPONSE variable
What is the relationship between independent and dependent variables called?
The correlation
What is the secondary name for the line of best fit?
+ What makes for the most accurate line?
The least squares line.
Minimizing the area of the squares created by the data (relative to the line) makes for the best line
What are the components of the line of best fit?
Beta 1: SS (xy) / SS (x)
Beta 0: y-avg - (x-avg)(Beta 1)
What values can a line of best fit predict?
(Can a line of best fit predict a value far outside the given data set?)
Line of best fit is only accurate within the x-values of the data set AND just outside of it.
A point too far away will not be accurately predicted.
What is the correlation coefficient?
(letter and definition)
It is denoted by R.
It measures the strength and the direction of the correlation between the dependent and independent variables
How does the value of the correlation coefficient relate to the strength of correlation? (3 points)
When R is near 1, the correlation is strong
When R is near 0, the correlation is weak
When R is negative it shows that there is a negative trend
What is the square of the correlation coefficient?
The coefficient of determination.
It shows what percentage of the variation in the dependent variable is justified by the line of best fit
Correlation vs. causation
Correlation: Tendency for 2 variables to change together (no influence)
Causation: A change in one variable directly causes a change in the other
What does it mean when there is a ‘spurious’ correlation?
The correlation is purely coincidental
