frequency#

Purpose#

Generate frequency table.

Format#

frequency(x, varlist[, sort])#

Parameters:

x (NxK dataframe) – Data.
varlist – Names or indices of variables to be counted. If names, should be entered as a formula string.

E.g "rep78 + foreign"; E.g "df ~ df2 + df3", "df1" categories will be reported in rows, separate columns will be returned for each category in "df1" and "df2".

Parameters:: sort (scalar) – Optional, indicator to sort from most frequent to least frequent categories. Set to 1 to sort. Default = 0.

Examples#

Single one-way table#

The simplest use of frequency() is a single one-way table:

// Load data
fname = getGAUSSHome("examples/auto2.dta");
auto2 = loadd(fname);

// Create frequency table for the 'rep78' variable in 'auto2'
frequency(auto2, "rep78");

This code prints the following table:

    Label     Count   Total %    Cum. %
     Poor         2     2.899     2.899
     Fair         8     11.59     14.49
  Average        30     43.48     57.97
     Good        18     26.09     84.06
Excellent        11     15.94       100
    Total        69       100

Sorted one-way table#

The one-way table can be sorted from most frequent to least frequent category using the optional sort input:

// Indicator for sorting
sort = 1;

// Create frequency table for the 'rep78' variable in 'auto2'
frequency(auto2, "rep78", sort);

This code prints the following tables:

    Label      Count   Total %    Cum. %
  Average         30     43.48     43.48
     Good         18     26.09     69.57
Excellent         11     15.94     85.51
     Fair          8     11.59      97.1
     Poor          2     2.899       100
    Total         69       100

Multiple one-way tables#

Adding mutiple RHS variables to the formula string results in multiple one-way tables:

// Load data
fname = getGAUSSHome("examples/auto2.dta");
auto2 = loadd(fname);

// Create frequency table for the 'rep78' and 'foreign' variable in 'auto2'
frequency(auto2, "rep78 + foreign");

This code prints the following tables:

    Label     Count   Total %    Cum. %
     Poor         2     2.899     2.899
     Fair         8     11.59     14.49
  Average        30     43.48     57.97
     Good        18     26.09     84.06
Excellent        11     15.94       100
    Total        69       100


    Label     Count   Total %    Cum. %
 Domestic        52     70.27     70.27
  Foreign        22     29.73       100
    Total        74       100

Two-way tables#

To create a two-way table, a variable is added on the LHS of the formula string in front of the "~":

// Load data
tips2 = loadd(getGAUSSHome("examples/tips2.dta"));

// Get two-way table of 'sex' vs. 'smoker'
frequency(tips2, "sex ~ smoker");

========================================
   sex               smoker
========================================
                  No       Yes     Total


Female            55        33        88
Male              99        60       159

Total            154        93       247