Here is a Covariance Shortcut:
Work around it by calculating the Correlation and solving for the CoVariance
r =COV(X,Y)/sx * sy
COV(X,Y) = r * sx * sy
Enter the Y’s and X’s
Y1 “Enter” X1 “sigma+”
Y2 “Enter” X2 “sigma+”
Y3 “Enter” X3 “sigma+”
Now calculate the sample std for x and y, “g” “s” “xy” “x” “STO” 0, this is your numerator
so that gets you the sample std for x and y and then multiple the two, that
1 “ENTER” “g” “xhat,r” “x<>y” = r “RCL” 0 “x” = COV(X,Y)
Problem Solved.
Section 6 of HP handbook pg. 97 under linear estimation states that whether you estimate an X val or Y val, it automatically calculates the correlation by hitting X<>Y.
Enjoy.