I am conducting a logistic regression on variables that were selected via LASSO (hpgenselect). I have a question about my methodology. (1) If I want to control for age and gender, do I exclude them from the lasso selection but include them in the logistic regression? Or do I include them in both the lasso and logistic regression? (2) Is it appropriate to use hpgenselect and follow up with logistic regression  - Thank you -  ... View more

I have previously used glmselect and hpgenselect for linear and logistic regression model selection however I have come across a question. I am working on a case/control (1:3) conditional logistic regression with a high number of parameters and would like to perform dimensional reduction, like lasso. However, hpgenselect does not allow for the consideration of 'strata'. In this scenario, would it be inappropriate to consider hpgenselect because of the lack of 'strata', and, if so, are there alternatives in SAS that I am unaware of?   Thank you -  ... View more

Hi, I am looking to determine whether two medians are not equal and attempt to estimate the median difference between the two. From my research, I have found this can be done by performing the Wilcoxon Mann u test and quantile regression. However, I am confused on interrupting the for results each. Below if my data, code for both, results, and interpretation. I think I am in the right direction but: Having trouble with the median difference estimate interpretation as well as understanding why the discrepancy in significance results. Happy to clarify anything that may have been unclear and appreciate the support. Mann U (npar1way) median a median b median diff pval (kruskalW) hodgeL Interpretation            601          642              41                 0.01 issue getting to load Median A and Median B are considered to be significantly different (difference=41, p<.05) as determined by the mannU test Quantile regression median a median b median diff                   pval Interpretation             601            642           34 (-74 - 143.78)     0.524 Median A and Median B are not considered to be significantly different (difference= 34.5 (-74.7 - 143.78), p=.52) as determined by quantile regression *Determine medians of the two groups; proc means data=test_data median; var y; class x; run; *Perform W-Mann-U test using KW for results; *HL for median difference not loading, useful?; proc npar1way data=test wilcoxon median; class x; var y; exact hl / maxtime=60; run; *Quantile regression to determine median difference estimate and signifiance difference; proc quantreg data=test_data; class x; model y= x/ quantile=.5; estimate x 1 -1 /CL; run;   ... View more

Hi,  I am comparing the trends of an interrupted segmented regression. I need some help understanding the relationship between my slope change and the p-value.   ... View more

Hi,  I am working on an intervention/ITS analysis. I first ran the analysis in R and would like to marginally replicate my results in SAS but I am having trouble. Given my ARIMA model from R and current proc arima code, I was hoping that you could point me in the right direction as the results do not make sense.   R model ARIMA=(3,0,0) proc arima data=one;      identify=y cross=(step ramp);      estimate p=3 input=(step ramp) method=ml outmodel=out;  run;   results SAS  R   Thank you!     ... View more

Hi,  I have a few ARIMA models (R) show below and I was looking to duplicate them using PROC AUTOREG and GARCH, however, I have not been able to replicate them to were they are relatively similar. I was hoping to see if it was possible and how it would fit into the proc autoreg statement. Models: ARIMA(0,0,0) ARIMA(4,0,0) ARIMA(0,0,2) ARIMA(1,0,0)(1,0,0)[12]   Thank you, ... View more