SAS is a proprietary cross-platform general-purpose statistical software package. [Official Website](http://www.sas.com/index.html)
4
votes
0answers
132 views
Specifying the linear predictor, survival function and PDF of a log-normal survival distribution
Continuing on my exploration of the log-normal distribution, I'm working on reimplementing some code originally written for a Weibull/Exponential model for a log-normal model. Among the things it does ...
4
votes
0answers
371 views
How are Kenward & Roger's degrees of freedom computed in PROC MIXED?
I run the following SAS model:
...
3
votes
0answers
115 views
Are GAMMs/GLM the best choice for calculating number of germs on hands?
We would like your opinion on whether GAMMs are a good option and how best to go about implementing for the following:
During a period of patient care, a nurse will accrue $Y$ colonies of bacteria on ...
3
votes
0answers
186 views
How to specify in r spatial covariance structure similar to SAS sp(pow) in a marginal model?
I'm currently translating existing code from SAS to R. I'm working on longitudinal data (CD4 count over time). I have the following SAS code :
...
3
votes
0answers
72 views
Prediction model problem
I am trying to design a model that can estimate the number of customers I will receive in every store every month using the number of customers I received every month in every store for the last five ...
3
votes
0answers
150 views
3
votes
0answers
145 views
Time Series: correcting the standard errors in a huge panel time series data set
I have stock returns at every 5 minute interval of each trading day for over 2 years for 40 stocks. I want to run a Fama-Macbeth regression by time interval (5min intervals) and then correct the ...
3
votes
0answers
352 views
Convergence failure with step-by-step parameter estimates in SAS proc logistic using the OFFSET option
I'm trying to fit a logistic model of the following form:
$$ y \sim \frac{1}{1 + \exp(-\beta_X)} $$
where
$$ \beta_X = a_0 + a_1x_1 + a_2x_2 + a_3x_3 + a_4x_4 + a_5x_5 $$
In my case, there is ...
3
votes
0answers
284 views
SAS proc mixed empirical standard errors
I'm fitting a 3 level mixed model and trying to compute empirical rather than model-based standard errors for the fixed effects. When specifying the empirical option in PROC MIXED, I get a warning ...
2
votes
0answers
20 views
Comparing two different but related datasets
Background: I used a principal component analysis to re-define neighborhood boundaries. Each neighborhood is made up of at least 2 census tracts. There were 40 neighborhoods in my old model. I have ...
2
votes
0answers
168 views
How to get correct Covariance components in SAS Proc mixed? Struggling with infinite likelihoods and negative variance components
I am trying to estimate covariance components from PROC MIXED and having trouble with convergence problems in the REML approach when I use the NOBOUNDS option. Let me explain why I am using NOBOUNDS ...
2
votes
0answers
63 views
Logistic Regression - Predicting an event with a couple time-related issues
I'm using logistic regression to predict the occurrence of tree carcasses falling after a mortality event. Data include a variety of topographic and tree characteristic variables and also time since ...
2
votes
0answers
93 views
How do I interpret this McNemar's agreement plot generated by SAS?
I'm running a simple McNemar's test for agreement on the McNemar's example from Wikipedia. The test uses the following data:
for patients of Hodgkin's disease. Running this SAS code:
...
2
votes
0answers
162 views
What do I do if my predicted values are out of the dependent variable range?
I have built a beta regression model with log link for predicting adherence. My dependent variable's range is 0 to 1.When I used a test set to calculate the predicted values with the parameter ...
2
votes
0answers
820 views
SAS PROC LOGISTIC: Hosmer and Lemeshow test is good but Gini is bad?
I am using PROC LOGISTIC along with Class statements to do binary logit model(default=1,non-default=0) on a bank loan dataset ...
2
votes
0answers
160 views
How SAS calculates PROC GLM
I'm trying to do a pairwise test to calculate p-values between various products that are being evaluated by several assessors. I'm trying to reproduce what SAS is doing in R, and I'm running into an ...
2
votes
0answers
182 views
How to calculate fitted values when using AdaBoost via gbm package in R? What does fitted values mean?
I poseted this question about two weeks ago. But it was closed because I cross-posted here and on SO. So I deleted the post on SO and re-post here. My question is as below.
First of all I'm not ...
2
votes
0answers
174 views
Multiplicative mixed models for analyzing variety-by-environment data
I got some nice data on multi-environmet trials (MET) data for genotype evaluation and would like to use some new developed techniques as discussed in Smith et. al 2005 Smith et. al 2005. I'm ...
2
votes
0answers
312 views
Interactions in Log Transformed DV
I built a fixed effects model using time series cross sectional data. The model was built using PROC MIXED in SAS. There are 2 effect coded attributes in the model and inteactions. One dummy ...
1
vote
0answers
59 views
Repeated Measures in R, SAS or SPSS: Whale Body Temperature Data
I have a question regarding a repeated measures experiment. I have 5 whales (randomly selected) that I recorded body temperature on. Data was collected via satellite, programmed to transmit records at ...
1
vote
0answers
32 views
Difference between GLM with intercept of subject VS repeated-measures ANOVA? [SAS code]
I've spent days trying to determine the difference between these two methods, which, as best I can tell, represent the univariate and multivariate approaches to a within-subjects design. Can anybody ...
1
vote
0answers
16 views
Survival analysis in SAS-is there a way to include a random effect with interval censored data?
I'm trying to use some form of survival analysis (e.g. accelerated failure time or proportional hazards) to study seed germination time. My data is interval censored (also called "grouped-time") and ...
1
vote
0answers
37 views
Avoiding the Generalized Variance Formula for the NYC Housing and Vacancy Survey
I am attempting to devise a replication-based survey design that closely replicates a taylor-series design used by the US Government publication - where I do not have access to all of the ...
1
vote
0answers
82 views
SAS error: variance covariance matrix singular
I am now working with a classmate on an estimate of an Almost Ideal Demand System for tobacco consumption. We have chosen to make an AIDS regression using goods tobacco and alchol, and the CPI price ...
1
vote
0answers
62 views
Covariate in generalized linear model with binary DV
I am comparing an offender group with a control group on a certain task in a generalized linear model with accuracy (0-1) as the DV. The reviewers criticized me by mentioning that one group was ...
1
vote
0answers
97 views
Sum of Squares reduction test: Convergence criteria met, but not all parameters of the model estimated
Background: I am using weighted non-linear regression to model the growth of plant organs, with dummy variables for different species. I am using a sum of squares reduction test (SSRT) to compare the ...
1
vote
0answers
169 views
Predicting a time-series based on level, season, and cycle
I have time-series data for stock price. A sample of dataset is given below:
...
1
vote
0answers
185 views
Simulating C4.5 algorithm using Decision Tree node in SAS Enterprise Miner 6.2.
In SAS Enterprise Miner 6.2 it's possible to approximate CHAID and CART methods using Decision Tree node, according to SAS Help, but there is nothing about C4.5 algorithm.
How can I mimic C4.5 ...
1
vote
0answers
198 views
Building a mixed model for multi-location split plot over 2 years in SAS
For the last 3 weeks I have been reading books, papers and internet sources incl. cross validated but could not find something that would work in my case.
I have data from a split-plot field trial.
...
1
vote
0answers
135 views
Spline df selection in a General Additive Poisson Model problem
I've been fitting some time series data using a Poisson general additive model using SAS's PROC GAM. Generally speaking, I've been having it's built-in generalized ...
1
vote
0answers
349 views
SAS optimal binning
In SAS enterprise miner we have the optimal binning feature which allows you to transform continuous variables into an ordered set of bins. The binning, as I read from one of their docs, is done so ...
1
vote
0answers
174 views
1
vote
0answers
234 views
How to draw B-spline plots via the PROC GLIMMIX procedure in SAS?
Recently I found that the PROC GLIMMIX procedure in SAS added a statement effect, which can handle B-spline in models. I tried ...
1
vote
0answers
303 views
Interpretation of a log likelihood function for PROC NLMIXED in SAS
I have a data set of skewed nutrient intake values, from around 7800 individuals, of whom around 3000 had two measures of daily nutrient intake (the others only had one measure), so this is a repeated ...
1
vote
0answers
106 views
Nonlinear mixed methods, Monte Carlo simulation and appropriate use of weighting for population distribution estimation
Note: I do not have access to SAS so I am trying to interpret the code off the macro syntax.
I have frequency-weighted data of nutrition intakes. The frequency ...
1
vote
0answers
266 views
How is the SAS REPLICATE statement in PROC NLMIXED different from a FREQ statement?
Note: I do not have access to SAS to work this out for myself.
I'm trying to work out the difference between the FREQ statement ...
1
vote
0answers
185 views
Good resources about reversible-jump MCMC sampler in R
Please help me to find out simple (I mean useful with little knowledge on Bayesian statistics) resources:
To learn MCMC and perform general linear or mixed models
To learn different sampling ...
0
votes
0answers
19 views
Different results from SAS PROC MIXED procedure and R lme function
I have 3(treatment)x3(period)x6(sequence) crossover design data. I have used SAS PROC MIXED procedure and I got the results with following code:
...
0
votes
0answers
17 views
Proc GENMOD estimate statement with 2 continuous variables?
I'm testing an ordinal scale measuring dyskinesia (range=0-4) via proc genmod, with the independent variables in the model being Drug1 and Drug2. Both of these variables are continuous. I want to ...
0
votes
0answers
19 views
Reporting predicted outcome of mixed effects models
I am analyzing some group-randomized longitudinal trial data with three time points using mixed effects model. Some people missed 1-2 time points, and I didn't exclude any cases with missing dependent ...
0
votes
0answers
62 views
How big of a dataset can R or SAS handle for regression?
On a standard computer (~3-6gb RAM) with 2 - 4 processors.
What are the size restrictions on a matrix of data for R or SAS?
0
votes
0answers
20 views
Estimating Smoothing Parameters Simultaneously with Regression Coeffecients
I am developing a forecasting model that relies on a smoothed leading indicator. The indicator is the ratio of two smoothed series, and the forecasting regression equation uses a lagged value of the ...
0
votes
0answers
29 views
Degrees of freedom for mixed model
Using data and code the example from http://www.ats.ucla.edu/stat/sas/faq/anovmix1.htm:
...
0
votes
0answers
45 views
What is the Survival Function using SAS LIFEREG with lognormal distribution?
I am trying to plot the survival curve using output from PROC LIFEREG with a lognormal distribution. Is my formula for the survival function (prob[i], where i is time) correct?
Below is my SAS code. ...
0
votes
0answers
37 views
Media or market mix modeling?
Can anyone tell me how to build media mix model? Is it similar to market mix model?
What are the steps and variables in the model? If I want to build in SAS which procedure should I use?
0
votes
0answers
30 views
Experimental design & model
I'm testing the effect of land history and soil organisms on the growth of Stinging nettle.
To investigate the effect of land history ("hist") on growth, soil samples ("sample") were collected at 10 ...
0
votes
0answers
61 views
Frequency Table for Repeated Measures
I've 12 unique subjects, and in total I've almost 1700 observations.
I've an ordinal response variable (has 4 levels) and 3 categorical covariates (each one has different levels 3, 5, 2, and 4 ...
0
votes
0answers
140 views
Results from multinomial ordinal logistic regression model
I've an ordinal response variable (has 4 levels) and 3 categorical covariates (each one has different levels 3, 5, 2, and 4 respectively). We also are dealing with repeated observations. I fitted a ...
0
votes
0answers
47 views
How do I get individual values of the random effect intercept in SPSS?
I am implementing a random intercept model in SPSS, and would like to obtain the subject-specific values of the random intercept to test it for normality. Does anyone know what's the SAS equivalent of ...
0
votes
0answers
102 views
Interpretation of sas output of survival Frailty model using Proc NLMIXED
I am new to the site, I am trying to fit a Weibull gamma frailty model in SAS for multiple event times per subject, using proc nlmixed procedure. Please how do I ...
