Left-truncated regression
Look at the sand package, which is available at http://www.csm.ornl.gov/esh/statoed/ and the NADA package, which is available from CRAN. One or both may have items of interest. Tom
Zita wrote:
Hi. I am looking for a function for left-truncated data. I have one data set with 2 variables (Hours~Yrs_Ed). I already left-censored the data at 200 and left-truncated it at the same spot, so that I am able to make 2 estimations (one for censoring and one for truncation). I know how to make the linear regression for the left-censored variable (hours) and how to plot the regression line into the (x,y) plot (packages AER, Zeileis, Survival, ...): tfit<-survreg(Surv(Hours,Hours>0, type='left')~Yrs_Ed,data=DataWomen,dist='gaussian') z<-predict(tfit,type="response") plot(Yrs_Ed,Hours) abline(tfit) My aim is to compare the effects of truncation and censoring graphically by plotting the two regression lines into one plot with both datasets (censored and truncated). I just can't figure out how to write the function for left-truncated data and what package to use for this. I only need "left-truncation", not "left-truncation and right-censoring". I hope somebody can help me with that matter. Zita
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