Normative comparisons for an observed value

Normative comparisons for an observed value

Usage

zScore(ref, value, by = NULL)

# S4 method for class 'NormativeReference'
zScore(ref, value, by = NULL)

percentPredicted(ref, value, by = NULL)

# S4 method for class 'NormativeReference'
percentPredicted(ref, value, by = NULL)

Arguments

ref

A NormativeReference.

value

Numeric observed value(s).

by

Named list or vector selecting the stratum (e.g. list(sex = "M", age = "60-69")); NULL when the reference has a single stratum.

Value

zScore() the standard score \((value - mean) / sd\); percentPredicted() \(100 \times value / mean\).

Examples

ref <- NormativeReference(
  "gait_speed",
  strata = data.frame(
    sex = c("M", "F"), mean = c(1.34, 1.24), sd = c(0.20, 0.19)
  ),
  source = "Bohannon 2011", unit = "m/s"
)
zScore(ref, 1.10, by = list(sex = "M"))
#> [1] -1.2
percentPredicted(ref, 1.10, by = list(sex = "M"))
#> [1] 82.08955