hp 49g+_user's guide_English_E_DCVL5300427_V2

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

+6.05x

+3.51x