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Head Circumference for age quantile, distribution, and zscore function based on LMS data from the CDC and WHO.

Usage

p_head_circumference_for_age(
  q,
  male,
  age,
  source = getOption("pedbp_pgs_source", "CDC"),
  ...
)

q_head_circumference_for_age(
  p,
  male,
  age,
  source = getOption("pedbp_pgs_source", "CDC"),
  ...
)

z_head_circumference_for_age(
  q,
  male,
  age,
  source = getOption("pedbp_pgs_source", "CDC"),
  ...
)

Arguments

q

a vector of quantiles

male

integer value, 1 = male, 0 = female

age

numeric age, in months

source

a character string denoting the data source providing the parameters needed for the estimate. Valid values are "CDC" and "WHO". This can be set explicitly, or by using the pedbp_pgs_source option.

...

pass through

p

a vector of probabilities

Value

p_ method return values from the estimated distribution function.

q_ methods return values from the estimated quantile function.

z_ methods return standard scores.

Notes

CDC Recommends using WHO growth charts for infants and children ages 0 to 2 years of age in the U.S. and CDC growth charts to monitor growth for children age 2 years and older in the U.S.

Examples


# The median head circumfernce for a two-year-old female:
q_head_circumference_for_age(p = 0.5, male = 0, age = 24, source = "CDC")
#> [1] 47.40516

# Find the percentile for a 13 month old male with a head circumfernce of 46 cm:
p <- p_head_circumference_for_age(q = 46, male = 1, age = 13, source = "CDC")
p
#> [1] 0.3482039

# the standard score is the quantile from a standard normal
z_head_circumference_for_age(q = 46, male = 1, age = 13, source = "CDC")
#> [1] -0.390174
qnorm(p)
#> [1] -0.390174

# WHO not yet implimented
tryCatch(q_head_circumference_for_age(0.5, male = 0, age = 24, source = "WHO"),
         error = function(e) e)
#> [1] 47.1799