I am trying to write a code that shows me the results of 1000 replications (I want to do a placebo test). I would like to end up with a matrix that shows the coefficient, the standard error and the t-value of the variable of interest (thus 3 columns, 1000 rows).

Assume that I am using the auto dataset, and I am running a regression and I am interested in the variable foreign. For the placebo test, I am assigning random values to foreign, re-running the regression, and storing the coefficients of foreign in a matrix (this is what I managed to do, see the code below). How can I expand this matrix so that it also includes the s.e. and t-value?

Code:
sysuse auto, clear

regress price weight mpg foreign 

count if foreign == 1
local numberforeign = r(N)

tempname resmat 

forv i=1(1)10 {

gen randomorder = runiform()
sort randomorder

drop foreign

gen foreign = 0
replace foreign = 1 in 1/`numberforeign'

regress price weight mpg foreign 

matrix `resmat'=nullmat(`resmat')\ e(b)

drop randomorder
}

matlist `resmat', format(%9.3f)

matrix V = `resmat'
matrix a = V[1..10 ,3..3]

mat list a