code>transf.dtorpb</code>: transformation of standardized mean differences to point-biserial correlations. Arguments <code>n1i</code> and <code>n2i</code> denote the number of individuals in the first and second group, respectively. If <code>n1i</code> and <code>n2i</code> are not specified, the function assumes <code>n1i = n2i</code> and uses the approximate formula <em></em>\(r_{pb} = \frac{d}{\sqrt{d^2 + 4}}\). If <code>n1i</code> and <code>n2i</code> are specified, the function uses the exact transforma