Standard Pac and Linear regression

11132019, 09:29 PM
Post: #14




RE: Standard Pac and Linear regression
If your interest extends to the archives, then hp41 howto do simple linear regression? (Posted by David E on 17 Dec 2002) should have modest appeal.
If you use the sigma+ button (top left on the keypad)(after clearing the summation registers using the CLSigma button  shift x<>y key, just below the sigma+ key), you can accumulate the sums of x, x^2, y, y^2, and xy in memory registers 11 through 15 respectively, while register 16 will get the value of n (the number of x,y pairs). To put in your numbers, enter y first, then "ENTER", and then enter your x value  then hit the sigma+ key. After you have entered all you pairs of values, you need to remember (or be told  or, left as an exercise for the student, derive!) the leastsquares fitting expressions for slope, intercept, and correlation coefficient. In case you are rusty: the slope is (n*SUMxy  SUMx*Sumy)/(n*SUMx^2  (Sumx)^2) the intercept has the numerator SUMy*SUMx^2  SUMxy*SUMx (with the same denominator as for the slope) r is (n*SUMXY  SUMx*SUMy) / ( SQRT(n*SUMx^2  (SUMx)^2) * SQRT(n*SUMy^2  (SUMy)^2) ) The above and more awaits your perusal. BEST! SlideRule 

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