Recently the CM Define It app featured the word probability and we thought it would be interesting to look at how popular this word has been over time using Google Books Ngram Viewer.
Figure 1. Frequency of use of the word probability over time, as a percentage of words in books indexed by Google Books
We’ve marked some important mathematical publications in the field of probability on the graph, but have they impacted common usage? After Laplace’s publication of Analytical Theory of Probability in 1812, usage steadily declined, and after Kolmogorov’s publication in 1933, usage of the word probability stayed flat for a while before going up, so there doesn’t appear to be much of a relationship. (There is a small caveat – these publications were not in English.)
Can we find another explanation for the trend? What if another word is competing for usage? Our first guess was that the term chance could somehow be involved. Here’s another graph:
Figure 2. Frequency of use of the words probability and chance over time, as a percentage of words in books indexed
That was a lucky guess! It appears that the use of the word probability increases as the use of the word chance decreases, and vice-versa. However, the total popularity of the two words has increased slowly but steadily over the 200-year period.
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