From "I wonder" to a clear question

By the end of this lesson you can rewrite a vague wonder as a clear question with a what, a who (or where) and a when.

Why it matters

"Which fruit sells best?" sounds like a clear question. In this lesson you will see it has three different right answers. If a manager asks a vague question and you answer a different one, all your careful work is wasted. Clear questions come first.

The idea in plain words

Imagine asking a friend to buy "some bread". They come back with one small roll. You wanted two big loaves. Nobody did anything wrong. The request was just not clear.

Questions about data are the same. Most start as an "I wonder": a vague idea. To turn it into a question that data can answer, you pin down three things:

1. What exactly are you counting or measuring? ("Best" is not a measurement. "Most items sold" is.)
2. Who or where is it about? (Amara's stall? All stalls in Lagos?)
3. When? (This week? This year?)

Clear question: a question that says exactly what to count or measure, who or where it is about, and when, so that only one answer is right.

Each step removes a guess. At the end, anyone with the data would get the same answer.

See it done

Amara asks: "Which fruit sells best?" She wants to know what to stock more of.

Data: market-stall-week.csv (synthetic).

1. Spot the vague word. "Best". It could mean three things: - the fruit with the most sales (the most rows), - the fruit with the most items sold (the most fruits handed over), - the fruit that brought in the most money.
2. See why it matters. Look at the answers for Amara's week. (Lesson 3.5 shows you how to work them out.) - Most sales: Orange and Watermelon, tied with 13 sales each. - Most items: Orange, with 103 items. - Most money: Watermelon, with ₦77,000.
3. Ask what Amara really needs. She wants to know what to stock more of. She stocks items, so "most items sold" fits best.
4. Add who and when. At Amara's stall, from 2 to 7 March 2026.
5. Write the clear question. "Which fruit had the most items sold at Amara's stall from 2 to 7 March 2026?"

Same week, same data, three different winners. The question decides the answer.

Your turn, with help

Lucía wonders: "Do my pupils live far away?"

Rewrite it as a clear question that her survey could answer.

Hint: her survey does not record distance. It does record travel_minutes. So "far" has to become something about minutes. Then add who and when.

Your turn, alone

Rewrite each wonder as a clear question. Say what, who or where, and when.

1. "Is Amara busy?"
2. "Do people like paying by card?"
3. "Is it hot in Lagos?"
4. Which of these two is clearer, and why? (a) "Which day is good for Amara?" (b) "On which day of the week of 2 to 7 March 2026 did Amara make the most sales?"

Watch out

• Vague words. Best, good, busy, popular, far, often. Each one hides a choice. Replace it with something you can count or measure.
• Forgetting "when". "How many sales?" Today? This week? Ever? Always say the time period.
• Answering a question nobody asked. Before you start, read your clear question back to the person who asked. "Is this what you meant?" saves hours.

Say it back

1. What three things does a clear question pin down?
2. Why does "which fruit sells best?" have three right answers?
3. Name one vague word to watch out for.

What is next

You have a clear question. Now: which rows of the table does it need, and which columns? Pick the wrong ones and the answer is wrong, even if your sums are perfect. Next lesson.