Tagged Questions

SAS is a proprietary cross-platform general-purpose statistical software package. [Official Website](http://www.sas.com/index.html)

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6 views

Proc Mixed for a random slopes model - contrast the slopes?

I have a need to make predictions about a set of students $^1$ who are nested under teachers, under schools, under districts. I have produced the below model, and I now wish to do some forecasting at ...
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1answer
23 views

How to compare repetitive data by using SAS? [on hold]

I have a question about how to code this change line data, in fact , i want to set up a dummy variable 'change line' = 1 or 0 by comparing different yes persons in different row , for example by ...
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0answers
17 views

Top coding: Replace outliers by the value of the mean +/- 6 times the standard deviation in SAS

I'm wondering if anyone can give me some help with this.. I'd like to perform a cluster analysis and this method is very sensitive to outliers. Therefore, top coding is used in similar research: ...
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0answers
18 views

A reduced regression in SAS [on hold]

I seek your help in modeling a reduced regression in SAS like the following: $Y_i+0.1X_{i1}-0.4X_{i2}=\beta_0+\beta_3X_{i3}+\beta_4X_{i4}+e_i$. The full model is ...
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0answers
9 views

Is there a SAS equivalent for JMP's life distribution?

I have a work flow where I use SAS to pull and prepare my data into censored data, and then open the SAS dataset in JMP and perform a life distribution analysis on the data. More often than not I use ...
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0answers
23 views

Possible to code contrasts comparing each level to grand mean with no reference category?

I'm working on a health care outcome regression model using the deviation contrast scheme described on the UCLA SAS help page here for a collection of dichotomous predictor variables measuring medical ...
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0answers
13 views

What are the right values for the prior mean and prior variance matrix in choice design?

I am doing my first choice experiment with JMP & the tutorial I found at http://blogs.sas.com/content/jmp/2009/01/15/optimal-design-of-the-choice-experiment/ Right now I am not sure if I ...
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1answer
56 views

Multicollinearity among categorical variables - Is it normal?

I'm building a logistic regression model in which almost all of the input variables are categorical. There are multiple sets of categorical variables, for example, day of the week, age range buckets, ...
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1answer
13 views

Confidence interval from summaries in JMP

If i only have mean, std dev. and number of observations is it then possible to generate af 95% confidence interval or a Chi squared test in JMP using only these summaries as input?
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37 views
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4 views

Make a prediction using SAS proc reg [migrated]

I am trying to create a prediction interval based on a linear model in SAS. My SAS code is ...
1
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0answers
122 views

Writing a coordinate descent algorithm for elastic net in SAS

In order to run Lasso and elastic net multiple regressions on my company's SAS server (which doesn't support R), I've been working on a coordinate descent macro for performing least squares ...
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0answers
10 views

Product Lifecyle Prediction using Survival Model

The project objective which I have is to come up with a model which would help forecast products which are close to the end of their lifecyle and need to be replaced. I was thinking whether this could ...
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0answers
17 views

Bagging in sas enterprise miner

I want to build a scorecard using logistic regression in sas enterprise miner. As I understand bagging will create subsets of my training data which in turn leads to more robust coefficients ...
1
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1answer
15 views

Testing GLIMMIX assumptions

I am currently doing GLIMMIX models in SAS. I choosed GLIMMIX as my data is count data, generally well described by a Poisson distribution. My question: What assumptions can you test to ensure that ...
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2answers
77 views

what does it mean when out of sample AUC is greater than in sample AUC?

I am fitting a logistic regression model on a data set with about 200,000 observation and 100 features. According to SAS output, the model converged correctly with an in-sample AUC of 0.85. However, ...
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4answers
510 views

How useful is Minitab in the real world? [closed]

I am currently a statistics student within a very good program. We use Minitab for a variety of items/classes. But, as my undergrad taught me, what you use in school isn't necessarily what is used in ...
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1answer
31 views

Why does the adjusted r-squared of this model improve with addition of a statistically insignificant variable?

I stumbled on this while doing MLR, and was curious as to why this happens. The adjusted R-squared is (if I understand correctly) supposed to be a way of comparing the predictive quality of models ...
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2answers
228 views

Why does SAS PROC GLIMMIX give me VERY different random slopes than glmer (lme4) for a binomial glmm

I am a user more familiar with R, and have been trying to estimate random slopes (selection coefficients) for about 35 individuals over 5 years for four habitat variables. The response variable is ...
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0answers
16 views

How can I code in SAS a tree to bin continuos variables?

I don't want to use SAS-Miner, because I want to create the code to do the optimal binning, even if it's only using entrophy criteria. Is there a code to do so? Thanks.
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0answers
48 views

Heteroskedasticity in a Linear Mixed Model SAS PROC MIXED

Asked a version of this question before but realized it needed some clarification. I have a dataset with identical twin pairs and fraternal twin pairs. I want to examine the relationship between an ...
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0answers
20 views

Apply LASSO Model with nominal target in SAS?

I'm building a classification model with a pool of independent variables (hundreds of them). I'm in the step of variable selection/feature selection. Now I'm trying to figure out if there are any ...
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0answers
30 views

Bootstrapping in SAS - PROC LOGISTIC - Next steps ? how to score / perform diagnostics?

My question is as follows. I am referencing the following paper by David Cassell - wherein David talks about bootstrapping techniques in SAS using PROC SURVEYSELECT (many thanks to David - truly a ...
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0answers
50 views

Linear trend in SAS using contrast

I've been struggling with this problem for a couple of hours, and I could use some advice. I have a linear regression model with two continuous predictors and a categorical one (with 4 levels). I ...
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0answers
22 views

How do I determine the innovation term in an ARIMA equation?

I am not a statistics specialist : I had to take over the internship subject of another student to include it in mine. He was working with $SARIMAX$ models and I would like to import them in an ...
2
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0answers
30 views

How do you test for trend in a generalized linear model, particularly for odd numbers of levels of a variable?

I'm trying to test for a trend across levels of a categorical variable using a contrast statement in a model and can not figure out how to do it when there are odd numbers of levels. Looking at SAS's ...
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0answers
62 views

Probability of Default

I'm doing a project to predict probability of delinquent for individual loans. Seems the model I fit is not good and I want to improve the model. However, I'm confused by the results I got and don't ...
2
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2answers
79 views

Objective test for proportionality assumption in Cox Regression Model (SAS)?

I was trying to fit Cox Regression (aka Proportional Hazard) model on some cancer data (N=2288). I got the following output from SAS proc phreg: ...
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0answers
31 views

Autoregressive model with input variables in proc arima procedure

I am currently working on the time series analysis for series Y but I have to use other two variable A and B as an input variable in SAS proc arima procedure. But I am unable to interpret the cross ...
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3answers
152 views

testing logistic regression coefficients using $t$ and residual deviance degrees of freedom

Summary: Is there any statistical theory to support the use of the $t$-distribution (with degrees of freedom based on the residual deviance) for tests of logistic regression coefficients, rather than ...
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0answers
58 views

How to get correlation between two categorical variable and a categorical variable and continuous variable?

I am building a regression model and I need to calculate the below to check for correlations Correlation between 2 Multi level categorical variables or 2 binary variables Correlation between a Multi ...
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2answers
51 views

How to analyze this messy design?

I need to analyze a data-set, with a very messy design, I am not sure how. I will try to make it simple. A new kind of stitches was invented, and is tested vs. 2 old kind of stitches. I will call ...
4
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3answers
132 views

Estimating the ratio of cell means in ANOVA under lognormal assumption

I am conducting a two-sample test (1-way ANOVA with 2 treatments), and the goal is to estimate the ratio of cell means assuming that the data are lognormal. A simple approach is to log the response ...
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0answers
24 views

SAS syntax to find differences in regards to a control treatment

I am working with a data set of bacterial cell counts, using flow cytometry. I recorded the cell number in 3 different species of bacteria, all treated with 3 different compounds (L-aspartic acid, ...
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2answers
82 views

Is it possible for Cramer's V to be negative?

To my understanding, Cramer's V cannot be negative because of the way we define it. But here's what I got from SAS:
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1answer
50 views

Wald test and Type III test don't agree?

I am having trouble understanding the output here. In the green table, it seems like SAS is saying "Gender F" and "Gender M" are not significant. However, in the blue table, seems like it's saying ...
0
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1answer
97 views

Too many p-value less than 0.0001 is alarming?

Can anyone explain why having too many p-value less than 0.001 is alarming? Like what happens to my model right now: All independent variables are categorical except for Calendar_Year. There are ...
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0answers
18 views

Logistics Regression Stoped at Step 0 with SAS Enterprise Miner

I use some insurance quote data with demographic data as variables and the target is binary (0,1). The total observations is around 50,000 and the variables are around 60. The demographic data is ...
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1answer
57 views

Concordance vs. Sensitivity

I am confused between these two terms: sensitivity and concordance. What I understand about these two terms: Concordance: the number of pairs where actual 1s have higher predicted probability of ...
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0answers
25 views

How to apply predict functionality of R in SAS?

do we have any proc or way that we can apply a model built on train dataset to test dataset using the predict function similar to R in SAS?
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0answers
33 views

Estimating the absolute decline of rates

Giving it another shot at describing my problem properly. I want to calculate the the crude event rates (10000person/years) for patients heart failure debut (variable name "heart_estimate") during ...
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0answers
44 views

Random effects models / Integrate over the random effect

I am trying to do maximum likelihood estimation and trying to see if the problem can be formulated using a random effect model. Here is the problem description: There are $100$ pairs $(N_i, D_i)$ ...
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1answer
57 views

Box Cox transformed my data, now how to use it in my mixed model? [closed]

Sorry for the (most likely) simple question, but I have Box Cox transformed my data in SAS, but I am unsure how to use the transformed data in my mixed model. Do I output it to a new file, and use ...
1
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1answer
82 views

Why does SAS Enterprise Miner keep all dummy variables for a coded categorical variable in stepwise logistic regression?

SAS Enterprise Miner nicely creates coded dummy variables for any categorical variables used in a logistic regression model. When it performs a variable selection using stepwise sequential selection ...
0
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0answers
25 views

Fitting a Mixed Model with Random and Repeated effects in SAS

I have want to fit a linear regression with repeated measures and random effects. The data come from clinical observations. In CT images The dependent variable is the diameter of a lymph node lesion ...
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0answers
40 views

Why are 'random' and 'repeated' in mixed models in SAS both producing the same result?

Why does SAS random and repeated both produce the same result? Can someone explain this in detail? For example: ...
2
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2answers
464 views

Can we use a coefficient of variation as a statistic for testing homogeneity of variance?

There are well-known HOV tests, for example Levene's, Brown-Forsythe's, Barlett's available in SAS and R. But $C_v$ also deals with dispersion, can we use it to understand the degree of HOV? July ...
3
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1answer
47 views

How to get only positive values when imputing data?

Suppose age is normally distributed with mean 20 and standard deviation 5. How do you ensure that you get only positive values when you sample age from this distribution? I am trying to impute ...
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0answers
37 views

How to apply the random statement in my model?

i am trying to model the following data in SAS using proc glimmix and i would like feedback if i have modelled my data correctly. My data consist of individual chickens (ID) who are grouped by ...
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0answers
11 views

ARIMA - is it normal to be unable to recover DGP of simulated data with 200,000 datapoints?

When learning how to use a statistical model, I often create a simulation of the DGP, and run simulated data through the software to make sure I know what I'm looking at. I've done this for Proc ...