Education Technology

Solution 12208: Calculating Covariance on TI Graphing Calculators.

How can I calculate covariance on my TI graphing calculator?

Covariance is a measure of linear relationship, like the coefficient of correlation. Actually, it is a step leading to the calculation of the correlation coefficient.

Covariance for a sample of data stored in the X and Y lists is given by [sum(x's - mean of x)(y's - mean of y)]/(n-1). The correlation coefficient is given by Covariance/(Sx*Sy), where Sx and Sy are standard deviations for x and y values respectively.

TI calculators, graphing or scientific, do not have to ability to calculate the covariance step. TI calculators only compute the correlation coefficient.