GENERATINGScatterplots

and Correlations

USING Ti84

plotting scatterplots using ti-84 / ti-89

Correlation measures the direction and

strength of the linear relationship between

two quantitative variables. Correlation is usually written as r

As always the summation sign __ means “add these terms for al the individuals,” is used in the formula for the correlation

“r.” (complex formula in stats)

to solve for the correlation of your data set, you will need to compute for:a) meanb) standard deviationc) z-score

You definitely need your

calculator to compute for

the correlation, which is still an arduous task to accomplish :)

Classifying Fossils: the length of two bones in five fossil specimens of the extinct beast

ARCHAEOPTERYX:

Femur 38 56 59 64 74

Humerus 41 63 70 72 84

r = .99

Possible correlations range from +1 to –1.

A zero correlation indicates that there is

no relationship between the variables.

A correlation of –1 indicates a perfect

negative correlation, meaning that as one

variable goes up, the other goes down.

A correlation of +1 indicates a perfect

positive correlation, meaning that both

variables move in the same direction

together.