About TomHsiung

TomHsiung · ‎03-07-2021

PROC REG DATA=WORK.D201; MODEL Average_daily_dose_during_the_in = Age__y_ Gender_code BSA AF Hypertension CHF Hypoalbuminemia_code AKI_for_T_test Potential_amiodarone_DDI T_test___indication VAR33 VAR34 AKI_2C9 AKI_VKORC1 / seleciton=stepwise SLE=0.05 SLS=0.20 vif clb clm cli; STORE WORK.DOSEMODEL / LABEL='Linear Regression'; RUN; PROC PLM RESTORE=WORK.DOSEMODEL ALPHA=0.05; SCORE DATA=WORK.PREDICTED out=WORK.NEWDOSE predicted lclm uclm; RUN; PROC PRINT DATA=WORK.NEWDOSE; VAR Age__y_ Gender_code BSA AF Hypertension CHF Hypoalbuminemia_code AKI_for_T_test Potential_amiodarone_DDI T_test___indication VAR33 VAR34 AKI_2C9 AKI_VKORC1 predicted lclm uclm; RUN; Just want to compute the confidence interval of dependent variable for new observations based on the result of a linear regression model. But no luck.

TomHsiung · ‎01-25-2018

I searched the Internet and found the code of / rl The complete code I used to make the Cox proportional hazard regression analysis is proc phreg data=work.d200; model Time_to_first_therapeutic_INR__d*First_therapeutic_INR_reached_(0)=age__y_ BSA gender_code af hypertension chf VAR94 AKI_for_T_test Potential_amiodarone_DDI T_test___indication AF_and_Warfarin_History var33 var34 / rl selection=stepwise SLE=0.05 SLS=0.20; assess ph / resample; run; Please pay attention to the last syntax of assess ph / resample; This code resulted in following output, what is that? Someone knows? This graph is interesting but it did not seem to like a goodness-of-fit test.

TomHsiung · ‎01-25-2018

By default, the PROC PHREG procedure results in a fixed value of hazard ratio, like in the screenshot below. PS: The confidence intervals of "Parameter Estimate" and "Hazard Ratio" were both missing. Based on the theory behind Cox proportional hazard model, I need the 95% CI. Tom

TomHsiung · ‎01-22-2018

Would you please make a example? The blog you mentioned is a bit difficult to understand. The syntax in the blog is not straightforward. Much appreciated! Tom

TomHsiung · ‎01-20-2018

Or is there any method to estimate the 95%CI and PI according to independent variables with pre-defined specific values. For instance, I set the age to 60 years, the body surface area to 1.73 m2, the serum albumin level to 30 g/L? Tom

TomHsiung · ‎01-19-2018

From references, I got the formulas to compute 95% confidence and 95% prediction intervals, respectively. To know the 95% CI and PI, "yhat" and standard error of the estimates must be known first. Luckily, yhat and standard error of the estimate could be estimated from he sample data set and the distributions of residual (y - yhat) and (yhat) are luckily normal. As a consequence, the 95% CI and PI could be computed. My issue is that my linear regression model has multiple predictors, including several continuous quantitative variables mixed with several other dummy (qualitative) variables. Those dummy variables are factors that divides my observations into two groups (presence of something, or absence of). I just want to know the 95% CI and PI for these two groups. SAS University Edition output a 95% CI and PI for each observation, which is not what I want. Tom PS: 95% CI after (simple) linear regression: And for 95% PI the formula is:

TomHsiung · ‎01-19-2018

I need to do much work. The State has a function called "margins". But it seems that margins did not output confidence interval of means by subgroups. Tom

TomHsiung · ‎01-18-2018

It's a little more difficult to understand. Tom

TomHsiung · ‎01-11-2018

Hi, Reeza Sorry for the delay. My intention is to get the 95% CI and PI for pre-defined groups. For short, the y response variable is average daily dose (mg), for example, and the predictor variables including continuous quantitative variables such as age, body surface area, serum concentration of albumin, and other dummy (qualitative) variables such as whether the congestive heart failure present, whether specific genotype present, whether hospitalization for longer than 14 days, etc. Obviously, the each qualitative variables divided these patients into two subgroups (the condition present or not). I want to know the 95% CI and PI for both subgroups. It's that when I am investigating the 95% CI and PI for both groups divided by a specific dummy variable, other predictor variables are adjusted (by the inherent nature of linear regression). I want to get the 95% CI and PI for the both subgroups. Tom

TomHsiung · ‎01-09-2018

proc reg data=work.d200; model average_daily_dose_during_the_in=age__y_ BSA gender_code af hypertension chf VAR94 AKI_for_T_test T_test___indication AF_and_Warfarin_History var33 var34 / selection=stepwise SLE=0.05 SLS=0.20 vif clb cli clm; run; The options of clm and cli would output the confidence and prediction intervals after the regression. But, the output was based on each individual observation. I want to know the overall confidence and prediction intervals based on each group of observations. How? Tom

TomHsiung · ‎01-06-2018

Much appreciated! Tom

TomHsiung · ‎01-06-2018

I think I need some basic study for SAS programing. I get to read some texts. Thank you. Tom

TomHsiung · ‎01-06-2018

Hi, Dray Thanks for your reply. I think I need some basic understanding of SAS programing and then more detail for multiple linear regression, logistic regression, and survival analysis. Tom

TomHsiung · ‎01-06-2018

1 OPTIONS NONOTES NOSTIMER NOSOURCE NOSYNTAXCHECK; 72 73 PROCEDURE PHREG DATA = work.d201 74 MODEl Time_to_first_therapeutic_INR__d*First_therapeutic_INR_reached_(0)=gender ;; _____ 22 76 ERROR 22-322: Syntax error, expecting one of the following: ;, (, ALPHA, ATRISK, BRIEF, BRIEFSUMMARY, CONCORDANCE, COVM, COVOUT, COVS, DATA, DETAILS, EV, EXPLVAR, FAST, IN, INEST, MULTIPASS, NAMELEN, NOPRINT, NOSUMMARY, OUT, OUTEST, PLOT, PLOTS, PRINT, ROCOPTIONS, SIMPLE, SUREV, TAU, TRACE, ZPH. ERROR 76-322: Syntax error, statement will be ignored. 75 run; NOTE: The SAS System stopped processing this step because of errors. NOTE: PROCEDURE PHREG used (Total process time): real time 0.00 seconds cpu time 0.00 seconds 76 77 OPTIONS NONOTES NOSTIMER NOSOURCE NOSYNTAXCHECK; 90 Just always got this error, I don't know what was wrong.

TomHsiung · ‎01-06-2018

It seems that many statistic procedures cannot be completed by the menu buttons. Instead the syntax could do everything. So any good books for the syntax? Tom

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