Calculates the number of answers by a specific sub-item
n_jk..(x, varindex, PA, p_ind = rep(1, nrow(x)))
A positive integer.
the data set to evaluate.
index of a particular sub-item.
set of possible linguistic terms.
a vector of the relative sampling weights of the units, for which \(length(p_ind) = nrow(data)\). If the weights are not relative, the following expression should be applied on the vector: $$\frac{p_{ind}}{\sum_{i=1}^{n} p_{ind}}.$$ If no sampling weights are used, the vector of weights is reduced to a vector of values 1, i.e. \(rep(1, nrow(data))\).