Methods for Storing and Analyzing Multiple Choice Variables

mChoice is a function that is useful for grouping variables that represent individual choices on a multiple choice question. These choices are typically factor or character values but may be of any type. Levels of component factor variables need not be the same; all unique levels (or unique character values) are collected over all of the multiple variables. Then a new character vector is formed with integer choice numbers separated by semicolons. Optimally, a database system would have exported the semicolon-separated character strings with a levels attribute containing strings defining value labels corresponding to the integer choice numbers. mChoice is a function for creating a multiple-choice variable after the fact. mChoice variables are explicitly handed by the describe and summary.formula functions. NAs or blanks in input variables are ignored.

format.mChoice will convert the multiple choice representation to text form by substituting levels for integer codes. as.double.mChoice converts the mChoice object to a binary numeric matrix, one column per used level (or all levels of drop=FALSE. This is called by the user by invoking as.numeric. There is a print method and a summary method, and a print method for the summary.mChoice object. The summary method computes frequencies of all two-way choice combinations, the frequencies of the top 5 combinations, information about which other choices are present when each given choice is present, and the frequency distribution of the number of choices per observation. This summary output is used in the describe function. The print method returns an html character string if options(prType='html') is in effect if render=FALSE or renders the html otherwise. This is used by print.describe and is most effective when short=TRUE is specified to summary.

in.mChoice creates a logical vector the same length as x whose elements are TRUE when the observation in x contains at least one of the codes or value labels in the second argument.

match.mChoice creates an integer vector of the indexes of all elements in table which contain any of the speicified levels

nmChoice returns an integer vector of the number of choices that were made

is.mChoice returns TRUE is the argument is a multiple choice variable.

Usage

mChoice(..., label='',
        sort.levels=c('original','alphabetic'), 
        add.none=FALSE, drop=TRUE, ignoreNA=TRUE)

# S3 method for class 'mChoice'
format(x, minlength=NULL, sep=";", ...)

# S3 method for class 'mChoice'
as.double(x, drop=FALSE, ...)

# S3 method for class 'mChoice'
print(x, quote=FALSE, max.levels=NULL,
       width=getOption("width"), ...)

# S3 method for class 'mChoice'
as.character(x, ...)

# S3 method for class 'mChoice'
summary(object, ncombos=5, minlength=NULL,
  drop=TRUE, short=FALSE, ...)

# S3 method for class 'summary.mChoice'
print(x, prlabel=TRUE, render=TRUE, ...)

# S3 method for class 'mChoice'
x[..., drop = FALSE]

match.mChoice(x, table, nomatch=NA, incomparables=FALSE)

inmChoice(x, values, condition=c('any', 'all'))

inmChoicelike(x, values, condition=c('any', 'all'),
              ignore.case=FALSE, fixed=FALSE)

nmChoice(object)

is.mChoice(x)

# S3 method for class 'mChoice'
Summary(..., na.rm)

Arguments

na.rm: Logical: remove NA's from data
table: a vector (mChoice) of values to be matched against.
nomatch: value to return if a value for x does not exist in table.
incomparables: logical whether incomparable values should be compaired.
...: a series of vectors
label: a character string label attribute to attach to the matrix created by mChoice
sort.levels: set sort.levels="alphabetic" to sort the columns of the matrix created by mChoice alphabetically by category rather than by the original order of levels in component factor variables (if there were any input variables that were factors)
add.none: Set add.none to TRUE to make a new category 'none' if it doesn't already exist and if there is an observations with no choices selected.
drop: set drop=FALSE to keep unused factor levels as columns of the matrix produced by mChoice
ignoreNA: set to FALSE to keep any NAs present in data as a real level. Prior to Hmisc 4.7-2 FALSE was the default.
x: an object of class "mchoice" such as that created by mChoice. For is.mChoice is any object.
object: an object of class "mchoice" such as that created by mChoice
ncombos: maximum number of combos.
width: With of a line of text to be formated
quote: quote the output
max.levels: max levels to be displayed
minlength: By default no abbreviation of levels is done in format and summary. Specify a positive integer to use abbreviation in those functions. See abbreviate.
short: set to TRUE to have summary.mChoice use integer choice numbers in its tables, and to print the choice level definitions at the top
sep: character to use to separate levels when formatting
prlabel: set to FALSE to keep print.summary.mChoice from printing the variable label and number of unique values. Ignore for html output.
render: applies of options(prType='html') is in effect. Set to FALSE to return the html text instead of rendering the html.
values: a scalar or vector. If values is integer, it is the choice codes, and if it is a character vector, it is assumed to be value labels. For inmChoicelike values must be character strings which are pieces of choice labels.
condition: set to 'all' for inmChoice to require that all choices in values be present instead of the default of any of them present.
ignore.case: set to TRUE to have inmChoicelike ignore case in the data when matching on values
fixed: see grep

Value

mChoice returns a character vector of class "mChoice" plus attributes "levels" and "label". summary.mChoice returns an object of class "summary.mChoice". inmChoice and inmChoicelike return a logical vector. format.mChoice returns a character vector, and as.double.mChoice returns a binary numeric matrix. nmChoice returns an integer vector. print.summary.mChoice returns an html character string if options(prType='html') is in effect.

Author

Frank Harrell
Department of Biostatistics
Vanderbilt University
fh@fharrell.com

Examples

options(digits=3)
set.seed(3)
n <- 20
sex <- factor(sample(c("m","f"), n, rep=TRUE))
age <- rnorm(n, 50, 5)
treatment <- factor(sample(c("Drug","Placebo"), n, rep=TRUE))


# Generate a 3-choice variable; each of 3 variables has 5 possible levels
symp <- c('Headache','Stomach Ache','Hangnail',
          'Muscle Ache','Depressed')
symptom1 <- sample(symp, n, TRUE)
symptom2 <- sample(symp, n, TRUE)
symptom3 <- sample(symp, n, TRUE)
cbind(symptom1, symptom2, symptom3)[1:5,]
#>      symptom1       symptom2      symptom3      
#> [1,] "Hangnail"     "Headache"    "Headache"    
#> [2,] "Muscle Ache"  "Depressed"   "Depressed"   
#> [3,] "Muscle Ache"  "Hangnail"    "Muscle Ache" 
#> [4,] "Stomach Ache" "Muscle Ache" "Stomach Ache"
#> [5,] "Headache"     "Muscle Ache" "Depressed"   
Symptoms <- mChoice(symptom1, symptom2, symptom3, label='Primary Symptoms')
Symptoms
#>  [1] Hangnail;Headache                 Muscle Ache;Depressed            
#>  [3] Hangnail;Muscle Ache              Muscle Ache;Stomach Ache         
#>  [5] Muscle Ache;Headache;Depressed    Hangnail;Muscle Ache;Headache    
#>  [7] Stomach Ache;Headache;Depressed   Stomach Ache;Depressed           
#>  [9] Stomach Ache;Depressed            Muscle Ache;Depressed            
#> [11] Hangnail;Stomach Ache;Headache    Hangnail;Muscle Ache;Stomach Ache
#> [13] Hangnail;Stomach Ache;Depressed   Muscle Ache;Headache             
#> [15] Hangnail;Muscle Ache;Stomach Ache Hangnail;Stomach Ache;Headache   
#> [17] Depressed                         Hangnail;Muscle Ache;Headache    
#> [19] Stomach Ache;Headache             Muscle Ache;Stomach Ache;Headache
#> attr(,"label")
#> [1] Primary Symptoms
#> Levels: Hangnail Muscle Ache Stomach Ache Headache Depressed
print(Symptoms, long=TRUE)
#>  [1] Hangnail;Headache                 Muscle Ache;Depressed            
#>  [3] Hangnail;Muscle Ache              Muscle Ache;Stomach Ache         
#>  [5] Muscle Ache;Headache;Depressed    Hangnail;Muscle Ache;Headache    
#>  [7] Stomach Ache;Headache;Depressed   Stomach Ache;Depressed           
#>  [9] Stomach Ache;Depressed            Muscle Ache;Depressed            
#> [11] Hangnail;Stomach Ache;Headache    Hangnail;Muscle Ache;Stomach Ache
#> [13] Hangnail;Stomach Ache;Depressed   Muscle Ache;Headache             
#> [15] Hangnail;Muscle Ache;Stomach Ache Hangnail;Stomach Ache;Headache   
#> [17] Depressed                         Hangnail;Muscle Ache;Headache    
#> [19] Stomach Ache;Headache             Muscle Ache;Stomach Ache;Headache
#> attr(,"label")
#> [1] Primary Symptoms
#> Levels: Hangnail Muscle Ache Stomach Ache Headache Depressed
format(Symptoms[1:5])
#> [1] "Hangnail;Headache"              "Muscle Ache;Depressed"         
#> [3] "Hangnail;Muscle Ache"           "Muscle Ache;Stomach Ache"      
#> [5] "Muscle Ache;Headache;Depressed"
inmChoice(Symptoms,'Headache')
#>  [1]  TRUE FALSE FALSE FALSE  TRUE  TRUE  TRUE FALSE FALSE FALSE  TRUE FALSE
#> [13] FALSE  TRUE FALSE  TRUE FALSE  TRUE  TRUE  TRUE
inmChoicelike(Symptoms, 'head', ignore.case=TRUE)
#>  [1]  TRUE FALSE FALSE FALSE  TRUE  TRUE  TRUE FALSE FALSE FALSE  TRUE FALSE
#> [13] FALSE  TRUE FALSE  TRUE FALSE  TRUE  TRUE  TRUE
levels(Symptoms)
#> [1] "Hangnail"     "Muscle Ache"  "Stomach Ache" "Headache"     "Depressed"   
inmChoice(Symptoms, 3)
#>  [1] FALSE FALSE FALSE  TRUE FALSE FALSE  TRUE  TRUE  TRUE FALSE  TRUE  TRUE
#> [13]  TRUE FALSE  TRUE  TRUE FALSE FALSE  TRUE  TRUE
# Find all subjects with either of two symptoms
inmChoice(Symptoms, c('Headache','Hangnail'))
#>  [1]  TRUE FALSE  TRUE FALSE  TRUE  TRUE  TRUE FALSE FALSE FALSE  TRUE  TRUE
#> [13]  TRUE  TRUE  TRUE  TRUE FALSE  TRUE  TRUE  TRUE
# Note: In this example, some subjects have the same symptom checked
# multiple times; in practice these redundant selections would be NAs
# mChoice will ignore these redundant selections
# Find all subjects with both symptoms
inmChoice(Symptoms, c('Headache', 'Hangnail'), condition='all')
#>  [1]  TRUE FALSE FALSE FALSE FALSE  TRUE FALSE FALSE FALSE FALSE  TRUE FALSE
#> [13] FALSE FALSE FALSE  TRUE FALSE  TRUE FALSE FALSE

meanage <- N <- numeric(5)
for(j in 1:5) {
 meanage[j] <- mean(age[inmChoice(Symptoms,j)])
 N[j] <- sum(inmChoice(Symptoms,j))
}
names(meanage) <- names(N) <- levels(Symptoms)
meanage
#>     Hangnail  Muscle Ache Stomach Ache     Headache    Depressed 
#>         47.9         47.8         48.1         47.5         49.9 
N
#>     Hangnail  Muscle Ache Stomach Ache     Headache    Depressed 
#>            9           11           11           10            8 

# Manually compute mean age for 2 symptoms
mean(age[symptom1=='Headache' | symptom2=='Headache' | symptom3=='Headache'])
#> [1] 47.5
mean(age[symptom1=='Hangnail' | symptom2=='Hangnail' | symptom3=='Hangnail'])
#> [1] 47.9

summary(Symptoms)
#> 
#> 15 unique combinations
#> 
#> Primary Symptoms
#> 
#> Frequencies of Numbers of Choices Per Observation
#> 
#>  1  2  3 
#>  1  9 10 
#> 
#> Pairwise Frequencies (Diagonal Contains Marginal Frequencies)
#> 
#>              Hangnail Muscle Ache Stomach Ache Headache Depressed
#> Hangnail      9        5           5            5        1       
#> Muscle Ache           11           4            5        3       
#> Stomach Ache                      11            5        4       
#> Headache                                       10        2       
#> Depressed                                                8       
#> 
#>  Frequencies of Top 5 Combinations 
#> 
#>     Hangnail;Muscle Ache;Headache Hangnail;Muscle Ache;Stomach Ache 
#>                                 2                                 2 
#>    Hangnail;Stomach Ache;Headache             Muscle Ache;Depressed 
#>                                 2                                 2 
#>            Stomach Ache;Depressed 
#>                                 2 

#Frequency table sex*treatment, sex*Symptoms
summary(sex ~ treatment + Symptoms, fun=table)
#> sex      N= 20  
#> 
#> +---------+------------+--+--+-+
#> |         |            | N| f|m|
#> +---------+------------+--+--+-+
#> |treatment|        Drug|11| 6|5|
#> |         |     Placebo| 9| 7|2|
#> +---------+------------+--+--+-+
#> | Symptoms|    Hangnail| 9| 6|3|
#> |         | Muscle Ache|11| 8|3|
#> |         |Stomach Ache|11| 6|5|
#> |         |    Headache|10| 7|3|
#> |         |   Depressed| 8| 5|3|
#> +---------+------------+--+--+-+
#> |  Overall|            |20|13|7|
#> +---------+------------+--+--+-+
# Check:
ma <- inmChoice(Symptoms, 'Muscle Ache')
table(sex[ma])
#> 
#> f m 
#> 8 3 

# could also do:
# summary(sex ~ treatment + mChoice(symptom1,symptom2,symptom3), fun=table)

#Compute mean age, separately by 3 variables
summary(age ~ sex + treatment + Symptoms)
#> age      N= 20  
#> 
#> +---------+------------+--+----+
#> |         |            | N| age|
#> +---------+------------+--+----+
#> |      sex|           f|13|47.7|
#> |         |           m| 7|49.8|
#> +---------+------------+--+----+
#> |treatment|        Drug|11|47.4|
#> |         |     Placebo| 9|49.7|
#> +---------+------------+--+----+
#> | Symptoms|    Hangnail| 9|47.9|
#> |         | Muscle Ache|11|47.8|
#> |         |Stomach Ache|11|48.1|
#> |         |    Headache|10|47.5|
#> |         |   Depressed| 8|49.9|
#> +---------+------------+--+----+
#> |  Overall|            |20|48.4|
#> +---------+------------+--+----+


summary(age ~ sex + treatment + Symptoms, method="cross")
#> 
#>  mean by sex, treatment, Symptoms 
#> 
#>     sex treatment                          Symptoms  N  age
#> 1     f      Drug                         Depressed  0   NA
#> 2     m      Drug                         Depressed  0   NA
#> 3   ALL      Drug                         Depressed  0   NA
#> 4     f   Placebo                         Depressed  1 55.8
#> 5     m   Placebo                         Depressed  0   NA
#> 6   ALL   Placebo                         Depressed  1 55.8
#> 7     f       ALL                         Depressed  1 55.8
#> 8     m       ALL                         Depressed  0   NA
#> 9   ALL       ALL                         Depressed  1 55.8
#> 10    f      Drug                 Hangnail;Headache  0   NA
#> 11    m      Drug                 Hangnail;Headache  1 46.3
#> 12  ALL      Drug                 Hangnail;Headache  1 46.3
#> 13    f   Placebo                 Hangnail;Headache  0   NA
#> 14    m   Placebo                 Hangnail;Headache  0   NA
#> 15  ALL   Placebo                 Hangnail;Headache  0   NA
#> 16    f       ALL                 Hangnail;Headache  0   NA
#> 17    m       ALL                 Hangnail;Headache  1 46.3
#> 18  ALL       ALL                 Hangnail;Headache  1 46.3
#> 19    f      Drug              Hangnail;Muscle Ache  1 46.4
#> 20    m      Drug              Hangnail;Muscle Ache  0   NA
#> 21  ALL      Drug              Hangnail;Muscle Ache  1 46.4
#> 22    f   Placebo              Hangnail;Muscle Ache  0   NA
#> 23    m   Placebo              Hangnail;Muscle Ache  0   NA
#> 24  ALL   Placebo              Hangnail;Muscle Ache  0   NA
#> 25    f       ALL              Hangnail;Muscle Ache  1 46.4
#> 26    m       ALL              Hangnail;Muscle Ache  0   NA
#> 27  ALL       ALL              Hangnail;Muscle Ache  1 46.4
#> 28    f      Drug     Hangnail;Muscle Ache;Headache  1 48.5
#> 29    m      Drug     Hangnail;Muscle Ache;Headache  0   NA
#> 30  ALL      Drug     Hangnail;Muscle Ache;Headache  1 48.5
#> 31    f   Placebo     Hangnail;Muscle Ache;Headache  0   NA
#> 32    m   Placebo     Hangnail;Muscle Ache;Headache  1 55.1
#> 33  ALL   Placebo     Hangnail;Muscle Ache;Headache  1 55.1
#> 34    f       ALL     Hangnail;Muscle Ache;Headache  1 48.5
#> 35    m       ALL     Hangnail;Muscle Ache;Headache  1 55.1
#> 36  ALL       ALL     Hangnail;Muscle Ache;Headache  2 51.8
#> 37    f      Drug Hangnail;Muscle Ache;Stomach Ache  0   NA
#> 38    m      Drug Hangnail;Muscle Ache;Stomach Ache  0   NA
#> 39  ALL      Drug Hangnail;Muscle Ache;Stomach Ache  0   NA
#> 40    f   Placebo Hangnail;Muscle Ache;Stomach Ache  2 46.4
#> 41    m   Placebo Hangnail;Muscle Ache;Stomach Ache  0   NA
#> 42  ALL   Placebo Hangnail;Muscle Ache;Stomach Ache  2 46.4
#> 43    f       ALL Hangnail;Muscle Ache;Stomach Ache  2 46.4
#> 44    m       ALL Hangnail;Muscle Ache;Stomach Ache  0   NA
#> 45  ALL       ALL Hangnail;Muscle Ache;Stomach Ache  2 46.4
#> 46    f      Drug   Hangnail;Stomach Ache;Depressed  0   NA
#> 47    m      Drug   Hangnail;Stomach Ache;Depressed  1 49.0
#> 48  ALL      Drug   Hangnail;Stomach Ache;Depressed  1 49.0
#> 49    f   Placebo   Hangnail;Stomach Ache;Depressed  0   NA
#> 50    m   Placebo   Hangnail;Stomach Ache;Depressed  0   NA
#> 51  ALL   Placebo   Hangnail;Stomach Ache;Depressed  0   NA
#> 52    f       ALL   Hangnail;Stomach Ache;Depressed  0   NA
#> 53    m       ALL   Hangnail;Stomach Ache;Depressed  1 49.0
#> 54  ALL       ALL   Hangnail;Stomach Ache;Depressed  1 49.0
#> 55    f      Drug    Hangnail;Stomach Ache;Headache  1 46.3
#> 56    m      Drug    Hangnail;Stomach Ache;Headache  0   NA
#> 57  ALL      Drug    Hangnail;Stomach Ache;Headache  1 46.3
#> 58    f   Placebo    Hangnail;Stomach Ache;Headache  1 47.1
#> 59    m   Placebo    Hangnail;Stomach Ache;Headache  0   NA
#> 60  ALL   Placebo    Hangnail;Stomach Ache;Headache  1 47.1
#> 61    f       ALL    Hangnail;Stomach Ache;Headache  2 46.7
#> 62    m       ALL    Hangnail;Stomach Ache;Headache  0   NA
#> 63  ALL       ALL    Hangnail;Stomach Ache;Headache  2 46.7
#> 64    f      Drug             Muscle Ache;Depressed  0   NA
#> 65    m      Drug             Muscle Ache;Depressed  0   NA
#> 66  ALL      Drug             Muscle Ache;Depressed  0   NA
#> 67    f   Placebo             Muscle Ache;Depressed  2 47.7
#> 68    m   Placebo             Muscle Ache;Depressed  0   NA
#> 69  ALL   Placebo             Muscle Ache;Depressed  2 47.7
#> 70    f       ALL             Muscle Ache;Depressed  2 47.7
#> 71    m       ALL             Muscle Ache;Depressed  0   NA
#> 72  ALL       ALL             Muscle Ache;Depressed  2 47.7
#> 73    f      Drug              Muscle Ache;Headache  1 41.7
#> 74    m      Drug              Muscle Ache;Headache  0   NA
#> 75  ALL      Drug              Muscle Ache;Headache  1 41.7
#> 76    f   Placebo              Muscle Ache;Headache  0   NA
#> 77    m   Placebo              Muscle Ache;Headache  0   NA
#> 78  ALL   Placebo              Muscle Ache;Headache  0   NA
#> 79    f       ALL              Muscle Ache;Headache  1 41.7
#> 80    m       ALL              Muscle Ache;Headache  0   NA
#> 81  ALL       ALL              Muscle Ache;Headache  1 41.7
#> 82    f      Drug    Muscle Ache;Headache;Depressed  1 50.8
#> 83    m      Drug    Muscle Ache;Headache;Depressed  0   NA
#> 84  ALL      Drug    Muscle Ache;Headache;Depressed  1 50.8
#> 85    f   Placebo    Muscle Ache;Headache;Depressed  0   NA
#> 86    m   Placebo    Muscle Ache;Headache;Depressed  0   NA
#> 87  ALL   Placebo    Muscle Ache;Headache;Depressed  0   NA
#> 88    f       ALL    Muscle Ache;Headache;Depressed  1 50.8
#> 89    m       ALL    Muscle Ache;Headache;Depressed  0   NA
#> 90  ALL       ALL    Muscle Ache;Headache;Depressed  1 50.8
#> 91    f      Drug          Muscle Ache;Stomach Ache  0   NA
#> 92    m      Drug          Muscle Ache;Stomach Ache  0   NA
#> 93  ALL      Drug          Muscle Ache;Stomach Ache  0   NA
#> 94    f   Placebo          Muscle Ache;Stomach Ache  0   NA
#> 95    m   Placebo          Muscle Ache;Stomach Ache  1 51.3
#> 96  ALL   Placebo          Muscle Ache;Stomach Ache  1 51.3
#> 97    f       ALL          Muscle Ache;Stomach Ache  0   NA
#> 98    m       ALL          Muscle Ache;Stomach Ache  1 51.3
#> 99  ALL       ALL          Muscle Ache;Stomach Ache  1 51.3
#> 100   f      Drug Muscle Ache;Stomach Ache;Headache  0   NA
#> 101   m      Drug Muscle Ache;Stomach Ache;Headache  1 44.3
#> 102 ALL      Drug Muscle Ache;Stomach Ache;Headache  1 44.3
#> 103   f   Placebo Muscle Ache;Stomach Ache;Headache  0   NA
#> 104   m   Placebo Muscle Ache;Stomach Ache;Headache  0   NA
#> 105 ALL   Placebo Muscle Ache;Stomach Ache;Headache  0   NA
#> 106   f       ALL Muscle Ache;Stomach Ache;Headache  0   NA
#> 107   m       ALL Muscle Ache;Stomach Ache;Headache  1 44.3
#> 108 ALL       ALL Muscle Ache;Stomach Ache;Headache  1 44.3
#> 109   f      Drug            Stomach Ache;Depressed  0   NA
#> 110   m      Drug            Stomach Ache;Depressed  2 51.4
#> 111 ALL      Drug            Stomach Ache;Depressed  2 51.4
#> 112   f   Placebo            Stomach Ache;Depressed  0   NA
#> 113   m   Placebo            Stomach Ache;Depressed  0   NA
#> 114 ALL   Placebo            Stomach Ache;Depressed  0   NA
#> 115   f       ALL            Stomach Ache;Depressed  0   NA
#> 116   m       ALL            Stomach Ache;Depressed  2 51.4
#> 117 ALL       ALL            Stomach Ache;Depressed  2 51.4
#> 118   f      Drug             Stomach Ache;Headache  0   NA
#> 119   m      Drug             Stomach Ache;Headache  0   NA
#> 120 ALL      Drug             Stomach Ache;Headache  0   NA
#> 121   f   Placebo             Stomach Ache;Headache  1 49.6
#> 122   m   Placebo             Stomach Ache;Headache  0   NA
#> 123 ALL   Placebo             Stomach Ache;Headache  1 49.6
#> 124   f       ALL             Stomach Ache;Headache  1 49.6
#> 125   m       ALL             Stomach Ache;Headache  0   NA
#> 126 ALL       ALL             Stomach Ache;Headache  1 49.6
#> 127   f      Drug   Stomach Ache;Headache;Depressed  1 45.2
#> 128   m      Drug   Stomach Ache;Headache;Depressed  0   NA
#> 129 ALL      Drug   Stomach Ache;Headache;Depressed  1 45.2
#> 130   f   Placebo   Stomach Ache;Headache;Depressed  0   NA
#> 131   m   Placebo   Stomach Ache;Headache;Depressed  0   NA
#> 132 ALL   Placebo   Stomach Ache;Headache;Depressed  0   NA
#> 133   f       ALL   Stomach Ache;Headache;Depressed  1 45.2
#> 134   m       ALL   Stomach Ache;Headache;Depressed  0   NA
#> 135 ALL       ALL   Stomach Ache;Headache;Depressed  1 45.2
#> 136   f      Drug                               ALL  6 46.5
#> 137   m      Drug                               ALL  5 48.5
#> 138 ALL      Drug                               ALL 11 47.4
#> 139   f   Placebo                               ALL  7 48.7
#> 140   m   Placebo                               ALL  2 53.2
#> 141 ALL   Placebo                               ALL  9 49.7
#> 142   f       ALL                               ALL 13 47.7
#> 143   m       ALL                               ALL  7 49.8
#> 144 ALL       ALL                               ALL 20 48.4

f <- summary(treatment ~ age + sex + Symptoms, method="reverse", test=TRUE)
#> Warning: Chi-squared approximation may be incorrect
#> Warning: Chi-squared approximation may be incorrect
#> Warning: Chi-squared approximation may be incorrect
#> Warning: Chi-squared approximation may be incorrect
#> Warning: Chi-squared approximation may be incorrect
#> Warning: Chi-squared approximation may be incorrect
f
#> 
#> 
#> Descriptive Statistics by treatment
#> 
#> +---------------------------+----------------------+----------------------+------------------------------+
#> |                           |Drug                  |Placebo               |  Test                        |
#> |                           |(N=11)                |(N=9)                 |Statistic                     |
#> +---------------------------+----------------------+----------------------+------------------------------+
#> |age                        |        45.8/46.4/48.7|        47.1/49.6/51.3|   F=2.09 d.f.=1,18 P=0.166   |
#> +---------------------------+----------------------+----------------------+------------------------------+
#> |sex : m                    |           45%  (5)   |           22%  (2)   |Chi-square=1.17 d.f.=1 P=0.279|
#> +---------------------------+----------------------+----------------------+------------------------------+
#> |Primary Symptoms : Hangnail|           45%  (5)   |           44%  (4)   |Chi-square=0.00 d.f.=1 P=0.964|
#> +---------------------------+----------------------+----------------------+------------------------------+
#> |    Muscle Ache            |           45%  (5)   |           67%  (6)   |Chi-square=0.90 d.f.=1 P=0.343|
#> +---------------------------+----------------------+----------------------+------------------------------+
#> |    Stomach Ache           |           55%  (6)   |           56%  (5)   |Chi-square=0.00 d.f.=1 P=0.964|
#> +---------------------------+----------------------+----------------------+------------------------------+
#> |    Headache               |           64%  (7)   |           33%  (3)   |Chi-square=1.82 d.f.=1 P=0.178|
#> +---------------------------+----------------------+----------------------+------------------------------+
#> |    Depressed              |           45%  (5)   |           33%  (3)   |Chi-square=0.30 d.f.=1 P=0.582|
#> +---------------------------+----------------------+----------------------+------------------------------+
# trio of numbers represent 25th, 50th, 75th percentile
print(f, long=TRUE)
#> 
#> 
#> Descriptive Statistics by treatment
#> 
#> +----------------+----------------------+----------------------+------------------------------+
#> |                |Drug                  |Placebo               |  Test                        |
#> |                |(N=11)                |(N=9)                 |Statistic                     |
#> +----------------+----------------------+----------------------+------------------------------+
#> |age             |        45.8/46.4/48.7|        47.1/49.6/51.3|   F=2.09 d.f.=1,18 P=0.166   |
#> +----------------+----------------------+----------------------+------------------------------+
#> |sex             |                      |                      |Chi-square=1.17 d.f.=1 P=0.279|
#> +----------------+----------------------+----------------------+------------------------------+
#> |    m           |           45%  (5)   |           22%  (2)   |                              |
#> +----------------+----------------------+----------------------+------------------------------+
#> |Primary Symptoms|                      |                      |                              |
#> +----------------+----------------------+----------------------+------------------------------+
#> |    Hangnail    |           45%  (5)   |           44%  (4)   |Chi-square=0.00 d.f.=1 P=0.964|
#> +----------------+----------------------+----------------------+------------------------------+
#> |    Muscle Ache |           45%  (5)   |           67%  (6)   |Chi-square=0.90 d.f.=1 P=0.343|
#> +----------------+----------------------+----------------------+------------------------------+
#> |    Stomach Ache|           55%  (6)   |           56%  (5)   |Chi-square=0.00 d.f.=1 P=0.964|
#> +----------------+----------------------+----------------------+------------------------------+
#> |    Headache    |           64%  (7)   |           33%  (3)   |Chi-square=1.82 d.f.=1 P=0.178|
#> +----------------+----------------------+----------------------+------------------------------+
#> |    Depressed   |           45%  (5)   |           33%  (3)   |Chi-square=0.30 d.f.=1 P=0.582|
#> +----------------+----------------------+----------------------+------------------------------+