Function to find significant regions from an interaction

This function uses the contrast function from rms to find the threshold for significance from interactions.

Usage

findSigRegions(
  object,
  l1,
  l2,
  name.vary,
  lower,
  upper,
  alpha = 0.05,
  starts = 50
)

object: A fitted rms object
l1: the first set of values to fix for the contrast function
l2: the second set of values to fix for the contrast function
name.vary: the name of the model parameter to vary values for to find the threshold. Note that this should not be included in l1 or l2 arguments.
lower: The lower bound to search for values for the varying value
upper: The upper bound to search for values for the varying value
alpha: The significance threshold, defaults to .05
starts: Number of starting values to try between the lower and upper bounds.

A data table with notes if no convergence or significance thresholds (if any).

## make me