sitar (version 1.1.1)

apv_se: Bootstrap standard errors for SITAR peak velocity and age at peak velocity

Description

apv_se bootstraps a SITAR model to generate standard errors for age at peak velocity (apv) and peak velocity (pv).

Usage

apv_se(object, nboot = 10, seed = NULL, plot = FALSE, ...)

Arguments

object

SITAR model.

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, and the plot. See Details.

Value

a 2x2 array giving the mean and se of apv and pv, with attribute "bs" a tibble containing the bootstrap estimates of apv and pv, with NAs removed.

Details

The mean velocity curve to be bootstrapped can be modified with arguments subset, abc, xfun, yfun or ns.

If plot is TRUE, the original velocity curve is plotted along with each bootstrap sample's pv versus apv.

Examples

# NOT RUN {
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)
# }