confidence intervals for a proportion

[gok chandran]

Hello...
I have a very simple question... how can I get confidence intervals for a proportion obtained by a 'tab' command: eg. " tab x y, col "
Wish it was as simple as "tab x y, col ci " but to no avail.

I have a large population based study (n=3000; 200 variables) of child development scores and I just want to show initial proportions between variables with confidence intervals.



Thanks

Chand

[Marcos Almeida]

Hello Gok,

Welcome to the Stata Forum.

You may wish to type:

cii n_sample n_cases

Best,

Marcos

[Carlo Lazzaro]

Gok:
assuming you want binomial exact CI, you may want to try something along the line of the following example:

. cii proportions 100 60, exact

                                                         -- Binomial Exact --
    Variable |        Obs  Proportion    Std. Err.       [95% Conf. Interval]
-------------+---------------------------------------------------------------
             |        100          .6    .0489898        .4972092    .6967052

Conversely, if the variables you're interested in are already reported in your dataset, the following approach probably fits your needs:

. sysuse bplong.dta
(fictional blood-pressure data)


. ci proportions sex, exact

                                                         -- Binomial Exact --
    Variable |        Obs  Proportion    Std. Err.       [95% Conf. Interval]
-------------+---------------------------------------------------------------
         sex |        240          .5    .0322749         .435002     .564998

[Marcos Almeida]

Thank you vey much for the correction, Carlo. Only now I notice I forgot to type "proportions" in the Stata command. Best, Marcos.