<p>This is not an answer - but it's too big for a comment. Your writing is simply unreadable. It might be salvageable if you used good practices for scientific writing. Here are the specific complaints. </p>

<ol>
<li>Your question is not written in complete sentences. Remarks like this are meaningless:

<blockquote>
  <p>Given performance in columns, what is a predictor for which?... Generalise for any number of exams between pre and final.</p>
</blockquote></li>
<li>You refer to things that don't exist, like "row ID" and "student number" when there is no row ID <em>nor</em> student number. </li>
<li>You excessively use dependent clauses. I found this line the most unreadable of all:

<blockquote>
  <p>So, for example—using the regular Fail (F) is &lt; 50; Pass (P) is ≥50 &amp; ≤75; Distinction (D) is >75 &amp; ≤ 85; and High Distinction (HD) is >85—show which exam—and quartile—predicts a more favourable final exam outcome?</p>
</blockquote></li>
<li>You don't define terms, then seem to use different terms equivalently, "marks", "columns", "outcome", "categorical variables", "quartiles" all seem to refer to one or more exam marks.</li>
<li>You use shorthand and lazy typing when you need to specific. Here, what other "corresponding probabilities" might you be talking about. And what else could &amp;etc. possibly mean?

<blockquote>
  <p>&amp;etc., with corresponding probabilities (incl. p values).</p>
</blockquote></li>
<li>Your writing is full of unnecessary adverbs: 

<blockquote>
  <p>Given the <strong>following</strong> dataset... I'm <strong>essentially</strong> trying to figure out...What test can I use for <strong>numerically</strong> explaining.."</p>
</blockquote></li>
</ol>

<p>As a tip: when people are confused on a subject, they tend to explain "wide" when they need to explain "deep". If you use consistent terminology, follow a structured format (like data - task - problem), and permit yourself <strong>only one question mark</strong>, the writing could be improved significantly.</p>
