This is the class of visual inference simple cubic linear model, inherited from VI_MODEL.
See also
Parent class: VI_MODEL
New attributes: SIMPLE_CUBIC_MODEL$formula,
SIMPLE_CUBIC_MODEL$null_formula, SIMPLE_CUBIC_MODEL$alt_formula,
New methods: SIMPLE_CUBIC_MODEL$..init.., SIMPLE_CUBIC_MODEL$E,
SIMPLE_CUBIC_MODEL$sample_effect_size, SIMPLE_CUBIC_MODEL$set_prm