z.score {corpora}R Documentation

The z-score statistic for frequency counts (corpora)

Description

This function computes a z-score statistic for frequency counts, based on a normal approximation to the correct binomial distribution under the random sampling model.

Usage


z.score(k, n, p = 0.5, correct = TRUE)

Arguments

k

frequency of a type in the corpus (or an integer vector of frequencies)

n

number of tokens in the corpus, i.e. sample size (or an integer vector specifying the sizes of different samples)

p

null hypothesis, giving the assumed proportion of this type in the population (or a vector of proportions for different types and/or different populations)

correct

if TRUE, apply Yates' continuity correction (default)

Details

The z statistic is given by

% z := \frac{k - np}{\sqrt{n p (1-p)}}

When Yates' continuity correction is enabled, the absolute value of the numerator d := k - np is reduced by 1/2, but clamped to a non-negative value.

Value

The z-score corresponding to the specified data (or a vector of z-scores).

Author(s)

Stephanie Evert (Rlhttps://purl.org/stephanie.evert)

See Also

z.score.pval


[Package corpora version 0.5-1 Index]