This should be used in conjunction with analyze to
    set parameters controlling analysis; see examples.
Usage
params(
  offset = NULL,
  n_knots_exp = 4,
  n_knots_cal = 4,
  var_est = "model",
  var_est_type = "classic"
)Arguments
- offset
 A linear predictor offset term; see docs for `lme4::lmer`.
- n_knots_exp
 An integer; only relevant when exp_time="NCS". Specifies the number of knots to use for exposure time, including boundary knots. The spline basis includes an intercept, and the degree of the basis is equal to the number of knots.
- n_knots_cal
 An integer; only relevant when cal_time="NCS". Specifies the number of knots to use for calendar time, including boundary knots. The spline basis includes an intercept, and the degree of the basis is equal to the number of knots.
- var_est
 A character string; either "model", for model-based variance, or "robust", to use the robust variance estimator.
- var_est_type
 A character string; one of c("classic","DF","KC","MD","FG"); only relevant when var_est="robust".
