Re: [R] Understanding cenros Error

2012-07-11 Thread Rich Shepard
On Wed, 11 Jul 2012, MacQueen, Don wrote: An my "easy" but not very useful answer is that this particular subset probably violates some assumption of the cenros() model. I myself would start with simple inspections of the data, such as with( subset(chem, param=='Ag'), table(ceneq1) ) with( s

Re: [R] Understanding cenros Error

2012-07-11 Thread MacQueen, Don
An my "easy" but not very useful answer is that this particular subset probably violates some assumption of the cenros() model. I myself would start with simple inspections of the data, such as with( subset(chem, param=='Ag'), table(ceneq1) ) with( subset(chem, param=='Ag'), qqnorm(quant) )

Re: [R] Understanding cenros Error

2012-07-11 Thread Rich Shepard
On Wed, 11 Jul 2012, Jim Lemon wrote: I don't have the NADA package, but I suspect that the cenros function is doing something like dividing by zero. With that much data, it may be hard to pinpoint where this is occurring. I would cut my data in half, run it, cut the remainder in half, run it an

Re: [R] Understanding cenros Error

2012-07-11 Thread Jim Lemon
On 07/11/2012 05:54 AM, Rich Shepard wrote: Before reading water chemistry into a data frame I removed all missing data. Yet when I try to run cenros() to summarize a specific chemical I get an error that I do not understand: with( subset(chem, param=='Ag'), cenros(quant,ceneq1) ) Error in lm.fi

[R] Understanding cenros Error

2012-07-10 Thread Rich Shepard
Before reading water chemistry into a data frame I removed all missing data. Yet when I try to run cenros() to summarize a specific chemical I get an error that I do not understand: with( subset(chem, param=='Ag'), cenros(quant,ceneq1) ) Error in lm.fit(x, y, offset = offset, singular.ok = sin