I want to study orthographical variants, for example:
Can firefighter, fire-fighter and fire fighter be considered orthographical variants (the difference in frequency in a corpus is not statistically/practically significant), or should one or more of these orthographical forms be considered "wrong"/"irregular" (the difference in frequency is statistically/practically significant)?
In a corpus of 926,766,504 words, I get the following frequency counts (on lemmas):
- firefighter = 3,349
- fire-fighter = 336
- fire fighter = 1,338
What statistical measure(s) can I use to say, for example, that there is not a large enough difference between firefighter and fire fighter to consider the latter "irregular", but that the difference between firefighter and fire-fighter is significant?
One specific sub-question:
If I work with probabilities (e.g. firefighter = 0,667; fire-fighter = 0,067; fire fighter = 0,266), is there a way to measure if the difference is significant? (Beyond just stating the obvious that the one occurs with a higher probability than the other.)