lab3

lab3#

data: transplants.dta

zoom: M T W Th F

This lab is optional; you are NOT required to complete these questions. Please use this lab as an opportunity to review the course material and prepare yourself for the homework questions. Sample responses to the lab questions will be on Friday April 21, 2023.

Start Stata, open your do-file editor, write the header, and load transplants.dta.
ctr_id indicates the ID of the transplant center where the patient received the transplant. Count the number of recipients at each center, and store in a new variable volume.
```
bysort ctr_id: gen volume=_N
```
List ctr_id and volume to see how many patients each center has. Maybe let’s try this:

list ctr_id volume
Whelp. This is not what we wanted. Generate a variable ctr_tag that “tags” one observation per center.
```
egen ctr_tag=tag(ctr_id)
```
Now list ctr_id and volume, but just for one record per center.
```
list ctr_id volume if ctr_tag==1
```
Calculate the mean age of the patients at each center, and store in a new variable mean_age.
```
bys ctr_id: egen mean_age=mean(age)
```
For each primary diagnosis subgroup (use variable dx), run a regression with age as the predictor and peak PRA (peak_pra) as the outcome.
```
forvalue i=1/9 {
        regress peak_pra age if dx==`i'
}
```

Now let’s make the output cleaner. Count the number of cases within each diagnosis group. If there are more than 500 cases, run the regression and display the output. If not, display “There are fewer than 500 cases.”

forvalue i=1/9 {
    qui count if dx==`i'
    if r(N)>500 {
          regress peak_pra age if dx==`i'
    } 
    else {
          di "There are fewer than 500 cases."
    }
}

Define a program called reg_pra. This program will perform the same tasks as described in Question 8, but the regression will take one or more variables specified by the user as the predictor.

capture program drop reg_pra
program define reg_pra
    syntax varlist

    forvalue i=1/9 {
        qui count if dx==`i'
        if r(N)>500 {
              regress peak_pra `varlist' if dx==`i'
        } 
        else {
              di "There are fewer than 500 cases."
        }
      }

end

You have all your commands in your do file, right? Run your do file from the beginning and make sure your do file does exactly the same thing.