# st: sampling question

 From "ACHINTYA RAY" To Subject st: sampling question Date Wed, 10 Mar 2004 12:58:38 -0600

```Sorry for posting a somewhat long query. I'll appreciate if you can help me
perform the following operation is Stata. Bootstrap commands in Stata helps
me perform some of the things. Specifically, I am looking for a solution
where (sort of) bootsrap is allowed within a bootstrap setup.

Suppose I have a sample of 20,000. I have 3 variables: y, x1 and x2.
Step 1: Draw 30 samples of size 100 each.
Step 2: Calculate mu(y), mu(x1), mu(x2) for each of the subsamples.
Step 3: Create a matrix of mu(y), mu(x1), mu(x2). Clearly, it will be a
matrix of dimension 30x3. Let's call it [Y X1 X2]
Step 4: Run the model Y=a + b1*X1 + b2*X2 + e
Step 5: Create file to save estimated b1 and b2.
Step 6: Repeat Steps 1 through 5 several times (100 times) to obtain a
matrix of estimated b1 and b2s (100x2 in dimension).

While I can create a grand file of all the means, I am having difficulty in
creating the subroutine described in Steps 1 through 5.

Thanks

Achintya Ray
Senior Research Associate
Department of Medicine
Vanderbilt University
achintya.ray@vanderbilt.edu

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