Presentation on theme: "SCATTERPLOT AND PERSONS PRODUCT- MOMENT CORRELATION COEFFICIENT. EXERCISE 2E AND 2F."— Presentation transcript:
SCATTERPLOT AND PERSONS PRODUCT- MOMENT CORRELATION COEFFICIENT. EXERCISE 2E AND 2F
A visual display of the relationship between two numerical variables. SCATTERPLOTS
SCATTERPLOT GALLERY POSITIVE RELETIONSHIP
PERFECT LINEAR RELATIONSHIP
NO LINEAR RELATIONSHIP
DESCRIBE THIS CORRELATION
SCATTERPLOT Decide whether or not a relationship exists between the variables and, if it does, comment on whether it is positive or negative; weak, moderate or strong: and whether or not it has a linear form
EXAMPLE Data showing the average weekly number of hours studied by each student in year 12 at Strathmore Secondary College and the corresponding height of each student.
PLEASE ADD THIS TO YOUR NOTES!!! THIS IS FOUND ON PG 87 OF YOUR TEXTBOOK.
There is a formula, but r is often done using CAS calculator. There are two limitations when using r: 1. Since r measures the strength of a linear relationship, it would be inappropriate to calculate r for data which are not linear. 2. Outliers can bias the value of r. Therefore, it will make it an unreliable measure of the strength of that linear relationship. CALCULATING R AND THE COEFFICIENT OF DETERMINATION WE MUST DRAW A SCATTERPLOT FIRST IN ORDER TO CHECK FOR A LINEAR FORM BEFORE r IS CALCULATED