topic Re: Creating SAS data set of parameter estimates from PROC NLIN in SAS Procedures

Creating SAS data set of parameter estimates from PROC NLIN

LMB — Tue, 18 Mar 2014 15:09:28 GMT

I have a data set containing 980 paired observations of fish length and age. I would like to use a bootstrapping approach to examine how sample size affects the precision of model parameter estimates.

I have used the following program to successfully create a dataset where 3 fish per cm length class are selected 1000 times from the original dataset:

PROC SURVEYSELECT DATA = AGE OUT = SAMPLE

METHOD = URS

N = 3

SEED = 9876

OUTHITS

REP = 1000;

STRATA TLINT;

RUN;

Next I fit model parameters to each replicate in this dataset:

PROC SORT DATA = SAMPLE;

BY REPLICATE;

RUN;

PROC NLIN DATA = SAMPLE;

PARMS LINF = 550 K = .25 t0 = 0.1;

MODEL TL = LINF*(1-EXP(-K*(AGE-t0)));

BY REPLICATE;

OUTPUT OUT = FITTED;

RUN;

I would like to create a dataset that contains parameter estimates for each replicate. The dataset would contain the following variables:

REPLICATE LINF K t0

and would look like this, for example:

1 568 .25 .02

2 520 .27 .14

3 491 .32 .01

etc.

I have also attached the SAS file.

Any help would be appreciated.

Re: Creating SAS data set of parameter estimates from PROC NLIN

PGStats — Tue, 18 Mar 2014 15:16:18 GMT

Try adding the statement:

ODS OUTPUT ParameterEstimates=samplePE;

to your NLIN procedure.

Re: Creating SAS data set of parameter estimates from PROC NLIN

LMB — Tue, 18 Mar 2014 16:22:28 GMT

PG,

That was helpful in summarizing the parameter estimates by replicate. However, is there a way to get them into a format that is easier to work with? Ideally this would be a SAS data set.

Re: Creating SAS data set of parameter estimates from PROC NLIN

LMB — Tue, 18 Mar 2014 16:32:24 GMT

Actually I may be ok working with it by exporting to Excel.

Re: Creating SAS data set of parameter estimates from PROC NLIN

PGStats — Tue, 18 Mar 2014 16:56:59 GMT

In the example I gave, samplePE would be a SAS dataset containing the parameter estimates. That seemed to be what you wanted.

Re: Creating SAS data set of parameter estimates from PROC NLIN

LMB — Tue, 18 Mar 2014 17:04:01 GMT

Got it. Thanks!