HP 48gII - Manual (Page 635)

Page 18-64
yv − ABS SQ Calculate SST
/ Calculate SSE/SST
NEG 1 + √ Calculate r = [1–SSE/SST ] 1/2
“r” TAG Tag result as “r”
SWAP Exchange stack levels 1 and 2
“SSE” TAG Tag result as SSE
» Close sub-program 4
» Close sub-program 3
» Close sub-program 2
» Close sub-program 1
» Close main program
Save this program under the name POLYR, to emphasize calculation of the
correlation coefficient r.
Using the POLYR program for values of p between 2 and 6 produce the
following table of values of the correlation coefficient, r, and the sum of
square errors, SSE:
p r SSE
2 0.9971908 10731140.01
3 0.9999768 88619.36
4 0.9999999
7.48
5 0.9999999 8.92
6 0.9999998 432.61
While the correlation coefficient is very close to 1.0 for all values of p in the
table, the values of SSE vary widely. The smallest value of SSE corresponds to
p = 4. Thus, you could select the preferred polynomial data fitting for the
original x-y data as:
y = 20.92-2.61x-1.52x 2 +6.05x 3 +3.51x 4 .