Fig 3. Data made with a straight-line model (1^st column) and results of analyses using null (2^nd column), straight-line (3^rd column) and quadratic (4^th column) models.

The four combinations (a-d) of low/high variance (σ) and effect size (α) represent approximate graphical extremes. Grey lines represent transitions in leading w_i between two models. “Traffic signal” colors on sample size (N) axes for the straight-line model indicate ranges where N is too small (red = stop), about equivalent to the null (yellow = caution), or sufficient (green = go) to correctly infer the pattern. Note the null and quadratic model outcomes at low N (red circles or ellipses).