Is LaTeX use correlated with the number of equations in a manuscript?

Astronomy papers are most frequently composed and submitted in either Microsoft Word or LaTeX format. While most journals accept submissions in Word format (and some, such as Meteoritics and Planetary Science, until recently required Word format), the majority of astronomy papers posted to the arXiV are submitted in LaTeX format. The wisdom of using LaTeX is sometimes questioned: for instance, a recent study demonstrated that a set of 40 researchers and graduate students were able to transcribe text and tables more quickly and with fewer errors using Word rather than LaTeX, although LaTeX proved similarly efficient when it came to transcribing equations and was more enjoyable to use. However, the study had all participants reproduce a given source text. We suspect that the use of Word may influence an author to include fewer equations when creating an original work. This is a difficult hypothesis to test directly, so we instead use a subset of arXiV submissions to probe whether the use of LaTeX is correlated with the number of standalone equations in a manuscript. We find that PDF-only manuscripts on the arXiV have roughly half as many equations as those with LaTeX source files.