L.4.1.1 WATTOX.SAS program statements (Cont.)

LABEL N='NO. OF REPLICATES'

MEANPCT='MEAN DILUTION WATER SURVIVAL'

S2POOL='POOLED VARIANCE'

DF='DEGREES OF FREEDOM, DF'

TALPHA='T VALUE FOR (1-ALPHA=0.95,DF)'

DMIN='MINIMUM SIGNIFICANT DIFFERENCE';

TITLE2 'POWER OF T-TEST TO DETECT A TRUE POPULATION

DIFFERENCE (D)';

TITLE3 'FROM MEAN DILUTION WATER SURVIVAL USING ARCSINE

TRANSFORMATION';

PROC PRINT LABEL NOOBS; VAR M N MEANPCT S2POOL DF TALPHA

DMIN;

DATA B3;

SET B2;

DO PCTDIFF=10 TO 50 BY 10;

SEDSURV=MEANPCT-PCTDIFF/100;

ARCSURV=ARSIN(SQRT(SEDSURV));

ARCDIFF=MEAN0-ARCSURV;

TBETA=(SQRT(N)*ARCDIFF)/SQRT(2*S2POOL)-TALPHA;

POWER=PROBT(TBETA,DF);

OUTPUT;

END;

LABEL PCTDIFF=' percent REDUCTION IN SURVIVAL FROM DIL.

WATER'

SEDSURV='100 percent ELUTRIATE SURVIVAL'

ARCSURV='ARCSINE 100 percent ELUTRIATE SURVIVAL'

ARCDIFF='D'

TBETA='T VALUE FOR (1-BETA,DF)';

PROC PRINT LABEL;

VAR PCTDIFF SEDSURV ARCSURV ARCDIFF TBETA POWER;

TITLE;

/* Calculate median lethal concentration using the PROBIT

procedure */

/* Define elutriate concentrations */

/* Plot predicted and observed mortalities */

TITLE >WATER COLUMN TOXICITY DATA=;

TITLE2 >PROBIT CALCULATION OF LC50';

DATA C; SET A0;

MORT=M-SURV;

SELECT (TRT);

WHEN (0) CONC=0;

WHEN (1) CONC=100;

WHEN (2) CONC=50;

WHEN (3) CONC=25;

WHEN (4) CONC=12.5;

END;

PROC PROBIT LOG;

MODEL MORT/M=CONC / LACKFIT INVERSECL D=NORMAL;

OUTPUT OUT=O P=PROB STD=STD XBETA=XBETA;

/* Note: other analyses may be requested by changing

D=NORMAL to D=LOGISTIC or */ /* D=GOMPERTZ in the MODEL

statement above */

DATA C; SET O;

MORT=MORT/M;

PROC GPLOT;

PLOT MORT*CONC='X' PROB*CONC='P' / OVERLAY;

L43

Appendix L Selected Resource Documents