[clinic · EX-06] Null questions for a real corpus

[akash-coded]

Exercise clinic. One long-running thread per exercise. Ask here rather than opening a
new thread — the answers accumulate where the next person will look for them.

Exercise: EX-06 — Null questions for a real corpus · difficulty 🟡

What this exercise asks

Read the exercise first; this thread is for when you are stuck, not instead of it.

Three ways people get stuck on this one

1. Nulls that are off-topic. A question about the weather is trivially unanswerable and measures nothing. A good null names real entities and asks something the corpus does not contain.

2. Nulls at an unrealistic base rate. Balancing the classes flatters every threshold — that is precisely the bug in #7.

3. Nulls that are accidentally answerable, because the fact is present somewhere you did not check.

How to ask here

Post the numbers you got, the config that produced them, and what you already tried.
A question with a measurement in it gets answered in one round trip; a question without one
takes three.

If you have finished it, post the write-up in Show and Tell with the
[solution · EX-06] prefix rather than here — this thread stays for people who are stuck.