Nick,
Thank you for your program. I deleted the previous messages from the
thread so let me restate what I would like to do: I am looking for a
way to save -tabulate- output (the frequencies and the percent
values) as a matrix. The program by Nick works with frequency weights
but when analytic weights are used the matrix is different from the
-tabulate- output.
. sysuse auto
. tab foreign [aw=weight]
Car type | Freq. Percent Cum.
------------+-----------------------------------
Domestic | 57.1261189 77.20 77.20
Foreign | 16.8738811 22.80 100.00
------------+-----------------------------------
Total | 74 100.00
. friedrich2 foreign [aw=weight], matrix(mat)
. mat list mat
mat[2,2]
freq percent
Domestic 52 70.270271
Foreign 22 29.729731
The original program uses -collapse (count)-. I changed this to
-collapse (sum)- but the result is the same. The -collapse-
documentation in the Reference Manual explains that with (count) the
unweighted and analytically weighted results are identical. With
(sum) I expected the unweighted and analytically weighted results to
be different. My copy of the manual has these definitions on page
211:
sum:
unweighted: sum(x_j), the sum of the variable
aweight: sum(v_j*x_j); v_j = (w_j normalized to sum to _N)
Is my interpretation of the definitions wrong or does -collapse
(sum)- with analytic weights not do what the manual states?
Friedrich Huebler
--- Nick Cox <[email protected]> wrote:
> Is this closer to what you want? Not very efficient, so
> can be much improved.
>
> program friedrich2
> version 8
> syntax varname [if] [in] [fweight aweight] , matrix(string)
>
> preserve
> tempvar freq
> gen `freq' = 1
> collapse (count) `freq' `if' `in' [`weight' `exp'], by(`varlist')
> rename `freq' freq
> egen percent = pc(freq)
> mkmat freq percent, mat(`matrix')
>
> forval i = 1/`= rowsof(`matrix')' {
> local name : label (`varlist') `= `varlist'[`i']'
> if `"`name'"' == "" local name = `varlist'[`i']
> if `"`name'"' == "." local name "missing"
> local names `"`names' `"`name'"' "'
> }
>
> matrix rownames `matrix' = `names'
> end
>
>
> Nick
> [email protected]
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