sampiling studetns from K out of N schools by 3 stratum leves?

[Ash_75]

I would be very happy to help.

First, note that my DATA is registered to every student in a classroom within a school.

My goal is to randomly sample K out of N schools in distict school
And in each out of the  K school, I want to sample to each level of the sample stratum1, a different number of students
When at 2 levels of the stratum1 we will randomly sample 4 students and at the third level we will sample 5 students.
 
I think to split the sample so that:
1- Samples K distinct  schools from N schools:

proc sort data=my_data ; by school;run;

data my_data ;set my_data ;
by school;
/*Placing a random number for school and for students*/
retain uSchool 0;
if first.school then uschool=ranuni(12222154);
ustudent=ranuni(8744);
run;

proc sql;

ctreate table distinct_schools as

select distinict school,uschool,stratum1, stratum2 , stratum3, stratum4

from my_data;

quit;

proc sort data=distinct_schools ; by uschool;run;

proc surveyselect data=distinct_schools  out=K_schools outsorting=k_schools_sort

method=srs sampsize=60 seed=1234;

control stratum2 stratum3  stratum4;

run;

2- and perform another sample,  sample 4 students from the 2 levels of stratum1 and at the third level we will sample 5 students.

of 4 ostudents from the K schools for the two tiers separately.
proc sql;

create table Students_frame as

select a.school,b.*

from distinct_schools  as a left join my_data as b

on a.school=b.school;

quit;

proc sort data=Students_frame; by  uSchool ustudent stratum1;run;

proc surveyselect data=Students_frameout=Students_sample outsorting=sort_Students_sample 

method=srs sampsize=( 4 4 5) seed=323161;

strata uschool stratum1;

control stratum2 stratum3  stratum4;

run;

Do you have another suggestion that you do the sampling in one stroke and not split in two?