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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
.