Bootstrap standard errors for SITAR peak velocity and age at peak velocity
apv_se bootstraps a SITAR model to generate standard errors for
age at peak velocity (apv) and peak velocity (pv).
apv_se(object, fun = getPeak, nboot = 10, seed = NULL, plot = FALSE, ...)
object |
SITAR model. |
fun |
function to extract apv and pv from velocity curve (default getPeak), alternative getTakeoff or getTrough. |
nboot |
number of bootstrap samples (default 10). |
seed |
integer to initialize the random number generator (default NULL). |
plot |
logical to control plotting (default FALSE). |
... |
optional arguments defining the velocity curve to be bootstrapped
( |
If plot is TRUE, the original velocity curve is plotted along with
each bootstrap sample's pv versus apv.
a 2x2 array giving the mean and standard error of apv and pv, with attribute "bs" a tibble containing the bootstrap estimates of apv and pv, with NAs removed.
Tim Cole tim.cole@ucl.ac.uk
data(heights) ## fit sitar model for height model <- sitar(x = age, y = height, id = id, data = heights, df = 4) ## bootstrap standard errors for age at peak velocity and peak velocity output <- apv_se(model, nboot=3, seed=111, plot=TRUE)
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