# The Pearson correlation coefficient is a measure of degree of linear relationship between two variables

Ashford 5: – Week 4 – Discussion 1

Your initial discussion thread is due on Day 3 (Thursday) and you have until Day 7 (Monday) to respond to your classmates. Your grade will reflect both the quality of your initial post and the depth of your responses. Reference the Discussion Forum Grading Rubric for guidance on how your discussion will be evaluated.

Guess the Correlation

The Pearson correlation coefficient is a measure of degree of linear relationship between two variables. There are many correlated variables in health research: weight and height, smoking and drinking, health behaviors, etc.

The bivariate scatter plot shown below illustrates a strong negative correlation between two variables:

Negative Correlation Graph

The next graph depicts a correlation of 1 (i.e. for a variable correlated with itself):

Correlation of 1 Graph

For this discussion, analyze the graph below which represents the correlation between weight (vertical axis; weight in pounds) and height (horizontal axis; height in inches). Do you think there is a negative or a positive correlation coefficient between these two variables? What value do you think this correlation coefficient will have? You do not need to be exact, but come up with a value you think would fit the given data. For the estimated value, what would be the coefficient of determination and what does it mean? Is this a strong correlation? Please explain.

Correlation of Weight and Height Graph

Guided Response: Review several of your classmates’ posts. Respond substantively to two peers. How strong or weak was their correlation? What factors affect the strength of the correlation? What about its statistical significance?