Statistics Chapter 4 Correlation Flashcards
What is bivariate data?
Data which has pairs of values for two variables
How can you represent bivariate data?
On a scatter diagram
Which variable is usually plotted on the horizontal axis?
The independent of explanatory variable
Which variable is usually plotted on the vertical axis?
The dependent or response variable
What is correlation?
Correlation describes the nature of the linear relationship between two variables
What are the types of correlation?
- strong negative ()
- weak negative
- no/zero linear correlation
- weak positive
- strong positive (/)
How do you determine if two variables have a causal relationship?
Consider the context of the question (and use common sense)
When can you draw a line of best fit on a scatter diagram?
When correlation is shown
What form is the regression line of y on x written in?
Y = a + bx
What does the coefficient b tell you int the regression line?
The change in y for each unit change in x
- if the data is positively correlated, b will be positive
- if the data is negatively correlated, b will be negative
What is interpolation?
Using the regression line to make predictions for values of the dependent variable that are within the range of the given data
What is extrapolation?
Making a prediction based on a value outside of the range of the given data
