deletions | additions       diff --git a/student gain.tex b/student gain.tex  index ef54c7d..d4dbd97 100644  --- a/student gain.tex  +++ b/student gain.tex 
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\end{equation}  where $S_{\mathrm{pre}}$, $S_{\mathrm{post}}$, and $S_{\mathrm{max}}$ are respectively the pre-test score, post-test score, and maximum score for student $i$.  The current pre-test is short---3 questions---and assesses knowledge of basic mechanics, spherical coordinates, and vector algebra. In subsequent editions of the course, we shall add questions on statistics (e.g., error in the mean, standard deviation of a population, and propagation of errors) and basic astronomy (e.g., inverse square law for flux, diffraction limit, and doppler Doppler  effect).