7 - Correlation

7 - Correlation - Chapter 8: Correlation Oftentimes, wish...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 8: Correlation Oftentimes, wish to use values on one variable to predict values on another variable College entrance exams and later grades Income level and health Age and traffic safety
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Want to know the correlation (measure of the degree of relationship between two variables) Greater the correlation, more accurately we can predict value on one variable from value on the other To calculate a correlation, need pairs of observations (scores on each of the two variables; X and Y)
Background image of page 2
Can get some indication from a bivariate distribution (e.g., frequencies of values in combinations of levels of two variables) 10 30 50 70 90 90 8 18 19 70 5 19 34 16 50 12 21 24 7 30 1 10 14 9 1 10 2 1 Psychology Exam Scores Math Exam Scores
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Scatter Diagram (scatterplot) graphs the bivariate distribution by placing dots at the values of the paired scores
Background image of page 4
Scatterplot of Economics and Sociology Grades 30 40 50 60 70 80 90 100 30 40 50 60 70 80 90 100 Economics Test Scores
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Correlation coefficients (including Pearson’s r) assume linear relationships between variables Relation that can be represented by a straight line
Background image of page 6
Scatterplot of Economics and Sociology Grades 30 40 50 60 70 80 90 100 30 40 50 60 70 80 90 100 Economics Test Scores
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Direction of a Correlation Positive Correlation As values on X increase, values on Y tend to
Background image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 24

7 - Correlation - Chapter 8: Correlation Oftentimes, wish...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online