Dataset:  salmonella.dat

Source: W.G. Alvord, J.H. Driver, L. Claxton, J.P. Creason (1990). "Methods
for Comparing Salmonella Mutagenicity Data Sets Using Nonlinear Models," 
Mutation Research, Vol. 240, pp. 177-194

Description: Data for 2 experiments relating growth (number of colonies)
of salmonella to dose. Model fit was:
Y = (b0+exp(b1+b2*ln(X)))*exp(-b3*X)
The second data set displays heteroskedasticity and can be fit by EWLS
X=0 is replaed with X=0.000001

Variables/Columns
Experiment (Day)   8
Dose    10-16
Yield   20-24