Questions tagged [sas]

SAS is a statistical software package. Use this tag for any on-topic question that (a) involves SAS either as a critical part of the question or expected answer, & (b) is not just about how to use SAS.

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15 views

adaptive randomization with ongoing enrollment

What is the best way to randomize existing participants at different sites in a 1:1 ratio to 2 intervention groups (group T or P) under the following conditions: Enrollment is ongoing so I’d like to ...
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out of sample prediction standard error and confidence limit using bootstrap

I am analyzing growth data to determine if sibling competition affect growth using GLIMMIX procedure in SAS with different class and continuous variables and 2 random effects. I want to predict out of ...
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Multiple imputation using proc mi EM method in SAS

I'd like to clarify how to use SAS for (multiple) imputation in SAS, specifically the EM method option for proc mi. Do I need to analyze multiple imputed sets using proc mianalyze as mentioned in ...
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Why does median() differ from quantile()[“50%”] in R and doesn't honor the type? Is this an estimator or sample quantile?

I just found, that when I want a specific type of quantile in R, say the number 3, it doesn't agree with median calculated in the "traditional way" in R. ...
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LASSO Regression with AIC or BIC as Model Selection Criterion

I am fitting a linear model using LASSO and exploring BIC (or AIC) as the selection criterion. The most useful resource I have stumbled upon is this earlier question here on CrossValidated: Is it ...
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Restricted Cubic Splines - Test Non-linearity in SAS

In SAS, I am having a very difficult time performing a formal test of non-linearity for the effect of one continuous variable estimated using restricted cubic splines. Yes, I know this is easy to ...
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14 views

Sample size for binary outcome and continuous (%) predictor

I have a project in which I have 60-70 samples. Outcome = binary (positive or negative case) Exposure = % of the time participants followed new guidelines (0-100%) Question - would it be correct to ...
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Logistic regression: How to generate Odds ratio table like in the image below

I am working on developing binaqry logistic regression model using SAS. I would like to generate the odds ratio and CI table like in the below image for the categorical variables. I am unable to ...
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Binary independent variables with missing values. Create dummy variables or not?

I am developing a prognostic model to predict an outcome. I have few binary variables with missing values, see below example. Is it better if I create dummy variables out of the below Gender variable ...
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Translate Mixed Models syntax from SAS to R (rewrite SAS proc mixed to R lmer)

Can anyone help me, please, to implement the SAS mixed model presented below in R lmer syntax? How to interpret such a model? <...
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Sas linear regression deciding on subgroups

I want to model the Total Volume as a function of the two variables Units and Price. I want to find out whether to model the total volume on the category as a whole or whether to model total volume by ...
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What type of statistical test should I perform?

What statistical technique would I need to carry out if I want to see if there is a significant differences in the number of units purchased when classifying observations based the variables Age, ...
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Comparing rates of hospital admissions or refusal rates year against year

I am trying to design a study for introducing a treatment and seeing if this would change rates of admission or leaving the hospital against medical advice. I would compare Jan-Dec 2020 (no tx offered)...
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SAS principal component analysis help [closed]

I have performed a principal component analysis on sas and have but my 15 variables into 4 factors so I have 4 new constructs. I now want to find out which of the original variables were important in ...
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Stationarity in SAS

I am reading the following page: https://documentation.sas.com/?cdcId=pgmsascdc&cdcVersion=9.4_3.4&docsetId=etsug&docsetTarget=etsug_arima_examples08.htm&locale=en I have a question: ...
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glmmTMB Kronecker direct product for crossed random effects

I am trying to replicate a model fit using SAS's Kronecker direct product covariance structure UN@AR(1) in glmmTMB. The model specification that I have currently is pretty close to SAS but something ...
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How to do covariate analysis in LTA and calculate p-values?

I am facing an issue in SAS when trying to do regression modelling using Proc LTA. I want to estimate odds ratios for transitional probabilities of 8 covariates. Although my model converges SAS is ...
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1answer
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Identify individual networks within dataset containing many (using SAS preferably)

I have a dataset of links/edges that looks something like the following (except significantly larger - approx. 50,000 links): ...
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Change over time in QOL score

Hoping someone might help point me in the right direction with some questions I had (newby at stats, with 0 experience doing analysis with questionnaire data). Let’s say I have some participants who ...
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1answer
73 views

Why do the coefficients of cross-sectional fixed effects and time fixed effects become zero?

I currently have a panel data set that contains the quarterly increment of loans initiated from more than 300 cities in China over the period from 2011Q1 to 2020Q2. I want to examine the impact of ...
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1answer
57 views

Mixed model effects - can the results in this paper be correct?

I've read the following paper about recall rates for information being higher when said information is supplemented with pictographs: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2656019/ and am a bit ...
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Comparing Blood pressure control and stroke within ethnic groups and between them

I was wondering if people would know what test to use. Using NHANES data, what are the BP control (proportion at <140 SBP and <90 DBP) rates according to presence vs. absence of self-reported ...
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Could anyone verify the MMRM model implemented in R with SAS against the estimates and degrees of freedom?

I'm trying to find out if the gls() procedure in R is equivalent to the REPEAT statement in SAS procedure for mixed models. In other words, I would like to check if R is able to run the MMRM model. ...
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Causal Mediation for Survival Analysis: Help with Popular SAS Macro

I am attempting a simple mediation analysis in a Cox model using a popular SAS Macro as described by here Importantly, the description of the macro is also given at https://cdn-links.lww.com/permalink/...
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Interpreting SAS output - Roots of AR Characteristic Polynomial

I urgently need help on interpreting the numbers from a SAS output on Characteristic Roots: The VARMAX Procedure The VARMAX Procedure Roots of AR Characteristic Polynomial Index Real Imaginary Modulus ...
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1answer
37 views

Constraining a parameter in a 4 level variable In a propensity score regression

I’m generating a propensity score using logistic regression in SAS. The model predicts compliance with a quality measure. I will match patients into groups who actually complied and not complied with ...
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1answer
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PLS procedure in SAS software

experts, I have a question about PLS procedure in SAS. The manual said that the prediction on new data is by combining training data and new data (new data dont have response values). I did ...
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177 views

Interaction with restricted cubic spline - comparison between SAS and R

When performing the same cox-regression in SAS and i R (including and interaction with a 3 knot restricted cubic spline), I receive different parameter estimates (i.e on age_spline 2). In my example ...
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2answers
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Compare regression coefficients within the same model

I ran a regression model with around 10 regression coefficients. I now want to test wether these regression coefficients are significantly different from one another. How do I do this? Is a Wald test ...
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Logistic regression with small and differing sample sizes

I asked this question on Stack Overflow and was encouraged to come here for more help regarding methodological limitations. Previous question: I ran the model in SAS and I can't make sense of the ...
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How does partial least squares algorithm return more than one factor?

My understanding of PLS regression is that we find an eigen vector such that it maximises the covariance between X(matrix of independent variables) and Y(vector/matrix of dependent variable) i.e. find ...
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What are the most likely reasons for convergence failure in back-fitting algorithm (GAM)?

I'm trying to build a binomial model using proc gam in SAS. When I include certain predictors as splines in the model , I get an error that the scoring algorithm ...
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21 views

Submitting Lasso Results For Publication

I am creating a model to predict cost of a particular surgery. I have n = ~20,000 and have >300 variables to choose from. I decided to use a 5 fold cross validation Lasso approach in SAS (proc ...
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Should I use fixed or random effects?

I have a healthcare data set with one (six meter walk test) and two predictors (baseline six meter walk test as a covariate, and days of treatment). We want to know if 6MWT improves over time (using ...
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Including all treatments in crossover design mixed model in SAS

I have a dataset effects of 3 treatments against ctrl on cell-lines collected from 4 donors. ...
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Validity of setting Singular=1 in proc GLM Contrast statement (SAS)

I am running a proc GLM in SAS with specific contrasts, one of which is included in the code below. With the following code, all my contrasts are always unestimable: ...
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1answer
45 views

logistic mixed model very large standard error

I'm running a logistic mixed model (in SAS) and these are my results: ...
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1answer
73 views

How to add error bar plots into a parameter table?

I saw a very neat and clear table in this paper https://link.springer.com/article/10.3758/s13421-018-0797-5: As shown above, the authors added error bars of parameter estimates into a table, which ...
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Exact logit but for multinomial or conditional logit?

Logit uses MLE, which exhibits bias in small samples. As a result there is a procedure "Exact Logit" that I believe uses a method different than MLE to account for this. Is there something similar ...
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1answer
88 views

Evaluating the importance of a unit-root

I have a monthly time series and I'm trying to determine if such set of data is stationary or not; the dataset is about composed by 160 record. Specifically, I'm running 2 test found in literature: ...
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1answer
11 views

What is the best way to examine the interaction between student gender at level 1 and instructor gender at level 2 in a multilevel model?

I am building a multilevel model with students at level 1 and instructors at level 2 and I have variables at each level to indicate the gender of the students and their instructors (see coding below). ...
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20 views

How to solve heavy-tails error terms in a linear regression model

I am doing a linear regression model using SAS. After box-cox transformation of the outcome variable from wage to lwage (log of wage). The residuals plot still not normally distributed. How to solve a ...
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19 views

How can I verify the linear hypothesis in a multiple logistic regression using SAS?

I have a multiple logistic regression where 2 of my independent variables are continuous. The rest are dichotomous. I am supposed to verify the linear hypothesis for the continuous variables. Is there ...
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15 views

Why in SAS proc glm, the SE of a difference just simply takes on the larger SE of the two means in comparison?

In SAS proc glm (simple one-way ANOVA), I noticed the SE of differences do not correspond to widely circulated uncertainty propagation technique (e.g. any variation of quadrature summation, pooled ...
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70 views

Converting SAS model to R model: treating intercept as random term

I have a binomial data set in SAS with the following column names: loc, trt, succ, fail I want the response to be the proportion of success, so in my data statement I have total = succ + fail My ...
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131 views

Scaling credit risk scorecard

I need to build a credit risk scorecard using logistic and linear regression. The variables using to predict are all dummies, where each dummy is a bin of some variable. Let's say the variable age, I ...
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1answer
12 views

internal process of proc mianalyze procedure [closed]

Does proc mi analyze in sas consider only estimates of imputed values or complete data sets that is imputed values as well as non imputed values?
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1answer
41 views

Poisson Regression with overload of zeroes SAS

I am testing different models for the best fit and most robust statistics to my data. My dataset contains over 50000 observations, approx. over 99.3% of the data are zeroes - such 0.7% are actual ...
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1answer
34 views

Can SAS Least Squares Means estimation algorithm be translated for a design matrix in Reference coding?

My question is whether it’s possible to compute lsmeans defined in this SAS algorithm if the design matrix is not in GLM form. In particular, in R, if one feeds that design to model.matrix(), then ...
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28 views

Interpreting Ljung-Box white-noise test p-value

Good evening all, I am having some trouble understanding the Ljung-Box white-noise test p-value from SAS Forecast. So there are lags where the p-value exceeds 0.05, meaning that we fail to reject the ...

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