Chapter 13: Regression and Correlation Flashcards
What is correlation and regression?
Statistical techniques are often used in relation with one another
What can you do with correlation and regression?
quantify the strength and direction of an association between variables
What is covary?
Two random variables are associated
What is regression?
For any given value of x we can predict the corresponding value of y, specific predictions based on an association
What is the correlation coefficient?
Number that quantifies the strength and direction of an association between variables
What numbers are correlations between?
1 and -1
What are the measures of association?
The variety of correlation coefficients
What do correlations measure?
Relationship between 2 variables (x and y)
Suppose that you have access to hospital records on patient age and their number of days spent in hospital. Your most appropriate measure of association would likely be ________.
Pearsons r
What can you say if no pattern appears to exist between variables?
Statistically independent
What is the strength variation in correlation?
0 and +- 1
What does a stronger pattern or association mean?
Larger the correlation coefficient
There is no such thing as a zero correlation.
False
A correlation coefficient distinguishes between independent and dependent variables.
false
Are a coefficient of -.35 and +.35 equally strong?
Yes can think of it as a continuum
What is the relationship between positive and negative correlations?
Positive go together, in negative they move apart