Determine mean/median/IQ range of age for two separate groups

Question

I have a dataset in Stata with variables age and carrier, an indicator for carrier of a particular disease.

Using univar age I am able to getsome descriptive statistics of age for the dataset, but now I want to compare mean/median/IQ range between carriers and non-carriers. Is there some way to do this?

I have tried one line so far:

univar age if carrier = 1

which resulted in invalid syntax error, r(198)

I had expected descriptive statistics of age when carrier is 1.

Answer 1

Sample Data

clear 
set obs 100
gen age = runiformint(18,70)
gen carrier = runiformint(0,1)

Summary Stats

There are several ways to get summary statistics in Stata, but one way is to use the tabstat command:

tabstat age, by(carrier) statistics(n mean sd min p25  median p75 max iqr)

Summary for variables: age
Group variable: carrier 

 carrier |         N      Mean        SD       Min       p25       p50       p75       Max       IQR
---------+------------------------------------------------------------------------------------------
       0 |        52  43.96154  16.45667        19        30      39.5        59        70        29
       1 |        48   48.4375  14.24692        20        39        49      60.5        69      21.5
---------+------------------------------------------------------------------------------------------
   Total |       100     46.11  15.52183        19        33        44      59.5        70      26.5
----------------------------------------------------------------------------------------------------

See help tabstat for additional statistics options.

Edited to mimic output of univar.

Answer 2

You'd have to search quite hard for univar if you had not heard of it already. It's community-contributed and dates from 1997 and 1999:

STB-51  sg67.1  . . . . . . . . . . . . . . . . . . . . . . . Update to univar
        (help univar if installed)  . . . . . . . . . . . . . .  J. R. Gleason
        9/99    pp.27--28; STB Reprints Vol 9, pp.159--161
        improvements and new options to univar


STB-36  sg67  . . . . . . . . . . . . . . . Univariate summaries with boxplots
        (help univar if installed)  . . . . . . . . . . . . . .  J. R. Gleason
        3/97    pp.23--25; STB Reprints Vol 6, pp.179--183
        command that offers a streamlined display of univariate summaries,
        including, optionally, text-mode boxplots

Looking at its help indicates that you need its by() option. Here's a reproducible example:

. sysuse auto, clear
(1978 automobile data)

. univar mpg, by(foreign)

-> foreign=Domestic 
                                        -------------- Quantiles --------------
Variable       n     Mean     S.D.      Min      .25      Mdn      .75      Max
-------------------------------------------------------------------------------
     mpg      52    19.83     4.74    12.00    16.50    19.00    22.00    34.00
-------------------------------------------------------------------------------

-> foreign=Foreign 
                                        -------------- Quantiles --------------
Variable       n     Mean     S.D.      Min      .25      Mdn      .75      Max
-------------------------------------------------------------------------------
     mpg      22    24.77     6.61    14.00    21.00    24.50    28.00    41.00
-------------------------------------------------------------------------------

Like @JR96, I recommend tabstat here.