st: Problems with -bs- command

 From "Paul Seed" <[email protected]> To <[email protected]> Subject st: Problems with -bs- command Date Wed, 7 Aug 2002 17:00:52 +0100

```Dear all,

I am interested in a bootstrapped confidence interval for the
difference between two means, and to save time
wish to work out the means using -summ, meanonly-.

I have written a Stata program to do this, which runs perfectly well
on it's own.  However, when trying to get -bs- to work out the confidence
intervals, I get an unexplained error message.

Any thoughts on wher ethe problem lies, greatly appreciated.

* Commands
cap prog drop myprog
prog define myprog, rclass
summ centile if aps, mean
di "r(mean) = " r(mean)
local m1 = r(mean)
return local m1 = r(mean)
summ centile if control, mean
return local m2 = r(mean)
return local m2_m1 = `m1' - r(mean)
end myprog

use centile1, clear
note

di in wh _n "Test program myprog"
myprog
ret li

di in wh "Now use it for bootstrap"
set seed 35435141
bs "myprog" "r(m1)", reps(50)
pause
bs "myprog" "r(m1)", reps(1000)

* Resulting output

. * Test program myprog"
.         myprog
r(mean) = 34.544

.         ret li

macros:
r(m2_m1) : "13.66652601350295"
r(m2) : "48.21052629579054"
r(m1) : "34.5440002822876"

.
. * Now use it for bootstrap"
.         set seed 35435141

.         bs "myprog" "r(m1) r(m2) r(m2_m1)", reps(50)

command:     myprog
statistics:  r(m1) r(m2) r(m2_m1)
error in statistic: r(m1)
r(198);

*
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```