Let $$\bar{z} = \sum_{i=1}^k \frac{z(p_i)}{k}$$
and $$s_{\bar{z}} = \frac{s_z}{\sqrt{k}}$$
Defined as
$$%
\frac{\bar{z}}{s_{\bar{z}}} > t_{k-1}(\alpha)
$$
The values of \(p_i\) should be such that \(0\le p_i\le 1\) and a warning is given if that is not true. An error is given if, possibly as a result of removing illegal values, fewer than two values remain.
As can be seen if all the \(p_i\) are equal or close
to equal this gives a \(t=\pm\infty\) leading to
a returned value of 0 or 1.
The plot method for class ‘metap
’ calls plotp
on the valid \(p\)-values.