* chlorophyll.txt, chapter 8 appendix;
/*************************************************************
           Chlorophyll-a in Lakes
Source: Smith and Shapiro (1981) in Environmental Science and
        Technology, volume 15, pages 444-451.
Data:
Column 1: Chlorophyll-a
Column 2: Phosphorus
Column 3: Nitrogren
************************************************************/
data lake;
input chlor phos nitro;
logc=log(chlor);
logp=log(phos);
logn=log(nitro);
datalines;
95.0 329.0 8
39.0 211.0 6
27.0 108.0 11
12.9 20.7 16
34.8 60.2 9
14.9 26.3 17
157.0 596.0 4
5.1 39.0 13
10.6 42.0 11
96.0 99.0 16
7.2 13.1 25
130.0 267.0 17
4.7 14.9 18
138.0 217.0 11
24.8 49.3 12
50.0 138.0 10
12.7 21.1 22
7.4 25.0 16
8.6 42.0 10
94.0 207.0 11
3.9 10.5 25
5.0 25.0 22
129.0 373.0 8
86.0 220.0 12
64.0 67.0 19
;
proc print;
run;
proc reg;
     model logc = logp;
     output out=a p=p r=r;
run;
proc plot;
     plot r*p/vref=0;
quit;