Actually, this is wrong. Sorry.
su typ_freq, meanonly
will almost always over-count.
count if !missing(type)
bysort type : gen typ_freq = _N / `r(N)' if !missing(type)
Nick
[email protected]
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of Nick Cox
> Sent: 04 November 2003 12:56
> To: [email protected]
> Subject: st: RE: generate new variable with frequencies
>
>
> The frequencies of -type- can be put
> in -typ_freq- by
>
> bysort type : gen typ_freq = _N
>
> If you want to scale to relative frequencies
> (sum 1) then you can
>
> su typ_freq, meanonly
> replace typ_freq = typ_freq / r(sum)
>
> and percents naturally can be obtained
> with a factor of 100.
>
> Some care will often be needed over
> missing values:
>
> bysort type : gen typ_freq = _N if !missing(type)
> su typ_freq, meanonly
> replace typ_freq = typ_freq / r(sum)
>
> Another way to do it:
>
> egen typ_freq = sum(1) if !missing(type), by(type)
>
> Nick
> [email protected]
>
> Matteo Foschi
> >
> > We have a little trouble with a, we think, easy task.
> > We want to generate a variable, which contains the relative
> > frequency of
> > another variable values.
> > We have a variable, say �type�, and want to built a new variable,
> > say �typ_freq�, which shows the relatively frequency of
> > each value of �type�.
> >
> > We have tried first with the tablepc ado-file:
> > tablepc type, generate (typ_freq)
> > Therefore we obtain only the relatively frequency of each
> > observation.
> >
> > We can obtain - in alternatively - the cumulated frequency
> > (variable freqcum)
> > with a little program:
> >
> > Generate freqcum =.
> > ..
> > sort typ_freq
> > by typ_freq: gen groups = 1 if _n ==1
> > replace groups = sum(groups)
> > ..
> > local K = groups[_N]
> > local i 1
> > while `i' <= `K' {
> > replace freqcum = sum(typ_freq)
> > local i = `i' + 1
> > }
> > ..
> > We are not able, however, to recode freq_cum or typ_freq
> > in order to obtain
> > the relatively frequency of each value of �type�, as bottom shows:
> >
> > Obs Type obs_freq freq_cum typ_freq
> > 1 1 1 1 2
> > 2 1 1 2 2
> > 3 2 1 3 3
> > 4 2 1 4 3
> > 5 2 1 5 3
> > 6 3 1 6 1
> > 7 4 1 7 2
> > 8 4 1 8 2
> > 9 5 1 9 1
> > 10 6 1 10 1
> >
>
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