SAS is a proprietary cross-platform general-purpose statistical software package. [Official Website](http://www.sas.com/index.html)
49
votes
20answers
11k views
R vs SAS, why is SAS prefered by private companies?
I learned R but it seems that companies are much more interested in SAS experience. What are the advantages of SAS over R?
14
votes
11answers
1k views
Best way to get started with and learn R
I have tried several times to "go it on my own" - but with limited success. I am a casual SPSS user and some SAS experience.
Would appreciate a pointer or two from someone who has similar background ...
13
votes
3answers
403 views
Resources for an R user who must learn SAS
I use R. Every day. I think in terms of data.frames, the apply() family of functions, object-oriented programming, vectorization, and ggplot2 geoms/aesthetics. I just started working for an ...
10
votes
2answers
1k views
What would a confidence interval around a predicted value from a mixed effects model mean?
I was looking at this page and noticed the methods for confidence intervals for lme and lmer in R. For those who don't know R, those are functions for generating mixed effects or multi-level models. ...
9
votes
2answers
2k views
Formula for autocorrelation in R vs. Excel
I am trying to figure out how R computes lag-k autocorrelation (apparently, it is the same formula used by Minitab and SAS), so that I can compare it to using Excel's CORREL function applied to the ...
8
votes
4answers
266 views
Out-of-Core Data Analysis Options
I have been using SAS professionally for close to 5 years now. I have it installed on my laptop and frequently have to analyze datasets with 1,000-2,000 variables and hundreds of thousands of ...
7
votes
5answers
2k views
Is there an R equivalent of SAS PROC FREQ?
Does anyone know of an R equivalent to SAS PROC FREQ?
I am trying to generate summary descriptive statistics for multiple variables at once.
7
votes
3answers
374 views
Using computer simulations to better understand statistical concepts at the graduate level
Hi I'm taking a graduate course in Statistics and we've been covering Test statistics, and other concepts.
However, I am often able to apply the formulas and develop a sort-of intuition on how stuff ...
7
votes
2answers
256 views
R as an alternative to SAS for large data
I know that R is not particularly helpful for analysing large datasets given that R loads all the data in memory whereas something like SAS does sequential analysis. That said, there are packages like ...
7
votes
2answers
2k views
Difference between ridge regression implementation in R and SAS
I have been reading the description of ridge regression in Applied Linear Statistical Models 5th Ed chapter 11. The ridge regression is done on a data set available at body fat data
The textbook ...
7
votes
1answer
134 views
How to find implementation details for a SAS procedure?
I was was wondering about where to track down implementation details for SAS: I have certain outputs (depending on small amounts of data) which I would like to understand better by trying to check ...
6
votes
4answers
2k views
Obtaining SAS experience
I have been looking at analyst job postings and one of the most common requirement is experience of SAS.
Unless your organisation currently uses SAS, how can you train as a SAS user?
What ...
6
votes
1answer
819 views
Convert SAS NLMIXED code for zero-inflated gamma regression to R
I'm trying to run a zero-inflated regression for a continuous response variable in R. I'm aware of a gamlss implementation, but I'd really like to try out this algorithm by Dale McLerran that is ...
6
votes
3answers
333 views
Binomial data analysis with all 0 responses for some treatment groups
We have a series of experiments where we measure virus transmission to plants when exposed to virus-infected insects for different time periods, so all of the experiments have similar types of ...
5
votes
3answers
295 views
Can I use a variable which has a non-linear relationship to the dependent variable in logistic regression?
Let's say I am building a logistic regression model where the dependent variable is binary and can take the values $0$ or $1$. Let the independent variables be $x_1, x_2, ..., x_m$ - there are $m$ ...
5
votes
4answers
815 views
Understanding multiple regression output
I am a first year psychology student. I am doing some research work with a prof, unfortunately the material that I need to use right now is covered only in my second year. But I need to already know ...
5
votes
2answers
283 views
Weird denominator degrees of freedom in SAS glimmix
I´m trying to learn generalized mixed models in SAS and I have now bumbed into a situation that I cannot figure out by myself. So I was thinking that maybe some of you could help me forward.
I´m ...
5
votes
1answer
329 views
R packages (or SAS code) to produce two simultaneous Kaplan-Meier curves?
There's a way to do survival analysis of two (or more I suppose) mutually exclusive competing risks as a mixture of two different survival curves. Something like what you see in A.C. Ghani et al. ...
5
votes
4answers
477 views
Improving accuracy of a binary classification when the target is unbalanced
I am working on the BRFSS dataset with the goal of predicting Diabetes. The dataset has 500,000 rows and 405 columns. It is a 0/1 classification problem, the ratio of 0 to 1 is 90:10. I tried using ...
5
votes
1answer
542 views
Bayesian Analysis in R/WinBUGS and SAS (Proc MCMC)
I have a Bayesian model here in R/WinBUGS. This data "pumps" has two columns, time and fail. Each observation is a pump and fail[1] tells how many failures there were in time[1]. I want to know how I ...
4
votes
1answer
2k views
Type III sum of squares from SAS and R
I'm analyzing data from an unbalanced factorial experiment both with SAS and R. Both SAS and ...
4
votes
2answers
552 views
Interactive decision trees
I was wondering if there is a free tool to build a decision tree in interactive fashion like in SAS Enterprise Mining. I'm used to work with Weka. But nothing fits to my needs. I would like that ...
4
votes
4answers
1k views
Open source Java library for statistics at the level offered by a graduate statistics course
I am taking a graduate course in Applied Statistics that uses the following textbook (to give you a feel for the level of the material being covered): Statistical Concepts and Methods, by G. K. ...
4
votes
2answers
101 views
ARIMA — Residual autocorrelation is non-significant upto lag 6 and significant beyond lag 6
I tried to fit an AR(1) model and was examining the estimates of the model. I had a question on the output (ran in SAS - Proc ARIMA):
The residual auto-correlation up to lag 6 was non-significant (in ...
4
votes
1answer
353 views
Equivalent mixed models yielding different results in SAS
Below I show two equivalent ways to write a mixed model in R and SAS. The two R models as well as the two SAS models yield the same estimates of the random and fixed effects and the same standard ...
4
votes
4answers
621 views
Regression for dependent variable with 4 categories
I want to do a regression where my dependent variable has four categories (1,2,3,4) which represents the number of dependents. Can I do this with logistic ...
4
votes
1answer
342 views
Replicating R model in SAS
I've got a model that I've developed in R, but also need to express in SAS. It's a double GLM, that is, I fit both the mean and (log-)variance as linear combinations of the predictors:
$E(Y) = ...
4
votes
1answer
2k views
How to perform logistic regression with lasso using GLMSELECT?
I am trying to perform logistic regression with lasso. For the logistic regression part I am using PROC LOGISTIC but I am not sure how to do lasso with ...
4
votes
1answer
343 views
Fitting a particular Gaussian model
Using R or SAS, I want to fit the following Gaussian model:
$$
\begin{pmatrix}
y_{1j1} \\ y_{1j2} \\ y_{1j3} \\ y_{2j1} \\ y_{2j2} \\ y_{2j3}
\end{pmatrix}
\sim_{\text{i.i.d.}}
{\cal N}
...
4
votes
1answer
780 views
How does one fit conditional Poisson regression in SAS?
I'm interested in fitting a conditional Poisson regression model using PROC GENMOD in SAS to analyze a matched cohort study. However, it's not quite clear to me how I should exactly go about it.
My ...
4
votes
1answer
284 views
Can we get confidence intervals for entries in stationary vector for an absorbing, time-independent Markov chain?
I have a finite-state, time-independent Markov chain with two absorbing states which models educational outcomes (the absorbing states are completing and not completing). The transition probabilities ...
4
votes
0answers
132 views
Specifying the linear predictor, survival function and PDF of a log-normal survival distribution
Continuing on my exploration of the log-normal distribution, I'm working on reimplementing some code originally written for a Weibull/Exponential model for a log-normal model. Among the things it does ...
4
votes
0answers
373 views
How are Kenward & Roger's degrees of freedom computed in PROC MIXED?
I run the following SAS model:
...
3
votes
4answers
641 views
When to use non-parametric regression?
I am using PROC GLM in SAS to fit a regression equation of the following form
$$
Y = b_0 + b_1X_1 + b_2X_2 + b_3X_3 + b_4t
$$
The QQ plot of the resulting redsiduals indicate deviation from ...
3
votes
2answers
889 views
Marginal effects of a logistic model, and their standard errors
I am using SAS to estimate some logistic models. Usually, I work with either MDs or social scientists, and odds ratios are the preferred metric. But I am now working with a client in economics/law and ...
3
votes
1answer
527 views
Cross-validation with sampling weights
I am trying to cross validate a logistic regression model with probability sampling weights (weights representing number of subjects in the population). I am not sure how to handle the weights in ...
3
votes
1answer
579 views
String replace in SAS?
Let's say I have a file A1.txt and a file A2.txt. I have written the statements
filename in1 'A1.txt';
filename in2 'A2.txt';
Now, I want to re-do this using B1 ...
3
votes
1answer
285 views
Time series modeling with dynamic regressors in SAS vs. in R
I am using both R and SAS for the time series modeling. There is an option in SAS that I could not find so far in any packages developed in R for the time series modeling such as TSA or forecast ...
3
votes
1answer
353 views
Survey weights in logistic regression models
We are interested in fitting a multiple logistic regression model using data obtained from a national survey of children with special health care needs. The data has an accompanying weight variable ...
3
votes
1answer
118 views
Logistic regression linear hyperplane
I'm performing logistic regression for binary classification in SAS and it outputs all of the coefficients to the logit model.
I was wondering how you would take those coefficients and use them to ...
3
votes
2answers
992 views
How to get convergence using coxph (R) given that model converges using proc phreg (SAS)
I have a data set
...
3
votes
1answer
317 views
PROC NLMIXED and PROC LIFEREG not arriving at the same answer for Log-normal survival function
Related question
I have a project where, despite being able to implement some parametric models in LIFEREG, it is somewhat more convenient to do it in NLMIXED. Verifying that this technique works, I ...
3
votes
1answer
104 views
What would be a good paper to cite to explain simulation methods in proc mixed in SAS?
In order to analyze data obtained from a repeated measure study, I used the following SAS code:
...
3
votes
1answer
344 views
How to choose an appropriate covariance structure for a simple one-way within-subjects RM ANOVA design?
It is postulated that one of the main issue is to find an appropriate covariance structure for repeated measures designs [Ref1]. SAS' PROC MIXED contains a number of covariance structures.
Despite ...
3
votes
1answer
91 views
How to pass character strings to R from IML Studio
If I define a function in IML:
start func(a);
submit a / R;
print(&a);
endsubmit;
finish;
and run it:
...
3
votes
2answers
519 views
Converting an SPSS file to a SAS file?
(I'm asking this question for a friend, honest...)
Is there an easy way to convert from
an SPSS file to a SAS file, which
preserves the formats AND labels?
Saving as a POR file gets me the
...
3
votes
1answer
197 views
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 ...
