Skip to contents

Calculate summary statistics for a variable

calc_stats.Rd

calc_stats() calculates summary statistics for a variable on groups. This is a generic function; note that it dispatches based on the class of target (second argument), not dt (first argument).

Usage

calc_stats(
  dt,
  target,
  target_name = target,
  treat,
  indent = nbsp(n = 4L),
  .total_dt = NULL,
  pct_dec = 1
)

Arguments

dt

A data.frame containing, at least, the variables indicated in target and treat.

target

Target variable passed as a string for which summary statistics are to be calculated.

target_name

Heading for the target variable as a string. Defaults to target.

treat

A string indicating the grouping variable, e.g. the variable specifying the treatment population.

indent

A string to be used as indentation of summary statistics labels. Defaults to four HTML non-breaking spaces ( ).

.total_dt

Separate table from dt from which to derive total counts per group.

pct_dec

Decimal places for reported figures.

Value

A data.table of summary statistics. The format depends on the type of the target variable:

  • If the target variable is categorical, i.e. type character, factor or logical then the output is that of calc_counts().

  • If the target variable is numeric, then the output is that of calc_desc().

Examples

# Calculate summary statistics of a numeric variable, e.g. `AGE`.
calc_stats(dt = adsl, "AGE", treat = "ARM")[[1]]
#>                                stats  A: Drug X B: Placebo C: Combination
#>                               <char>     <char>     <char>         <char>
#> 1:                               AGE                                     
#> 2:         &nbsp;&nbsp;&nbsp;&nbsp;n        134        134            132
#> 3: &nbsp;&nbsp;&nbsp;&nbsp;Mean (SD) 33.8 (6.6) 35.4 (7.9)     35.4 (7.7)
#> 4:    &nbsp;&nbsp;&nbsp;&nbsp;Median         33         35             35
#> 5:  &nbsp;&nbsp;&nbsp;&nbsp;Min, Max 21.0, 50.0 21.0, 62.0     20.0, 69.0
#> 6:   &nbsp;&nbsp;&nbsp;&nbsp;Missing          0          0              0

# Calculate summary statistics of a categorical variable, e.g. `SEX`.
calc_stats(dt = adsl, "SEX", treat = "ARM")[[1]]
#>                        stats A: Drug X B: Placebo C: Combination
#>                       <char>    <char>     <char>         <char>
#> 1:                       SEX                                    
#> 2: &nbsp;&nbsp;&nbsp;&nbsp;F        79         82             70
#> 3: &nbsp;&nbsp;&nbsp;&nbsp;M        55         52             62