test_cosinor_components function

Test for differences in a cosinor model between components.

Given a time variable and optional covariates, generate inference a cosinor fit. For the covariate named (or vector of covariates), this function performs a Wald test comparing the group with covariates equal to 1 to the group with covariates equal to 0. This may not be the desired result for continuous covariates.

test_cosinor_components(
  x,
  x_str = NULL,
  param = "amp",
  comparison_A = 1,
  comparison_B = 2,
  level_index = 0,
  ci_level = 0.95
)

Arguments

• x: An cglmm object.
• x_str: A character. The name of the grouping variable within which differences in the selected cosinor characteristic (amplitude or acrophase) will be tested. If there is no grouping variable in the model, then this can be left as NULL (default).
• param: A character. Either "amp" or "acr" for testing differences in amplitude or acrophase, respectively.
• comparison_A: An integer. Refers to the component number that is to act as the reference group. for the comparison.
• comparison_B: An integer. Refers to the component number that is to act as the comparator group
• level_index: An integer. If comparison_type = "components", level_index indicates which level of the grouping variable is being used for the comparison between components.
• ci_level: The level for calculated confidence intervals. Defaults to 0.95.

Returns

Returns a test_cosinor object.

Examples

data_2_component <- simulate_cosinor(
  n = 10000,
  mesor = 5,
  amp = c(2, 5),
  acro = c(0, pi),
  beta.mesor = 4,
  beta.amp = c(3, 4),
  beta.acro = c(0, pi / 2),
  family = "gaussian",
  n_components = 2,
  period = c(10, 12),
  beta.group = TRUE
)
mod_2_component <- cglmm(
  Y ~ group + amp_acro(times,
    n_components = 2, group = "group",
    period = c(10, 12)
  ),
  data = data_2_component
)
test_cosinor_components(mod_2_component, param = "amp", x_str = "group")