What data is: writing down what we notice

By the end of this lesson you can say what data is, and record five real observations as your first tiny table.

Why it matters

Every big decision in a shop, a school or a hospital starts with someone writing something down. If nobody writes it down, nobody can check it later. In this lesson you will write down your first data, today.

The idea in plain words

Meet Amara. Amara sells fruit from a stall in Lagos, Nigeria. It is Tuesday morning. A customer walks up and says, "Four pawpaws, please!"

Amara could just take the money and forget it. But Amara wants to know which fruit sells best. So she grabs her notebook and writes down what she noticed:

• the day: Tuesday
• the time: 09:40
• the fruit: pawpaw
• how many: 4
• how they paid: cash

That is all data is. Data is what we notice about the world, written down so we can look at it later.

Data: facts we notice and write down, such as numbers, words or dates.

Observation: one thing we noticed and wrote down. "The customer bought 4 pawpaws" is one observation.

There is one more trick. Amara writes every sale the same way, in the same order. Day, time, fruit, how many, how paid. Because she does that, her notes line up into neat rows. Data that lines up like this is called a table.

Table: data laid out in lines across and lines down, so every fact has its own box.

One sale at Amara's stall becomes one line of a table. The day, the fruit and the number each get their own box.

See it done

Here are Amara's first three Tuesday sales, just as she noticed them:

1. At 07:23 a customer bought 6 bananas and paid cash.
2. At 09:32 a customer bought 3 pineapples and paid cash.
3. At 09:40 a customer bought 4 pawpaws and paid cash.

Now watch how they become a table. Follow the steps.

1. Pick what to write down. Amara chooses five things: day, time, fruit, quantity (how many) and payment.
2. Make one heading for each thing. These go along the top: day, time, fruit, quantity, payment.
3. Give each sale its own line. Sale 1 goes on the first line, sale 2 on the next, and so on.
4. Put each fact under its heading. "6" goes under quantity. "Cash" goes under payment.

Three sentences became three tidy lines. Each line is one sale.

Look at the third line: Tue | 09:40 | Pawpaw | 4 | Cash. That is the "Four pawpaws, please!" sale. You just turned a moment at a market into data.

Your turn, with help

Amara writes down two more sales from later on Tuesday:

• At 12:03 a customer bought 7 oranges and paid by card.
• At 12:31 a customer bought 3 pawpaws and paid cash.

Task: write these two sales as two new lines, using the same five headings, in the same order.

Hint: start each line with the day. Then the time, then the fruit, then how many, then how they paid.

Show the answer

day	time	fruit	quantity	payment
Tue	12:03	Orange	7	Card
Tue	12:31	Pawpaw	3	Cash

If your order of headings was different, that is fine for now, as long as every line uses the same order.

Your turn, alone

This is your first real data. You will collect it yourself.

1. Pick something you can watch for five minutes. For example: people walking past your window, cars on a road, birds at a tree, or messages arriving on your phone.
2. Choose three things to notice each time. For cars you might choose: time, colour, type (car, bus, motorbike).
3. Write the three headings across the top of a page.
4. Each time one passes, write one new line. Stop when you have five lines.
5. Check: does every line have something under every heading?

Check your work

There is no single right answer, because this is your data. A good table looks something like this made-up example:

time	colour	type
16:02	white	car
16:03	yellow	bus
16:03	red	motorbike
16:05	white	car
16:06	black	car

Your table is good if: it has 3 headings, it has 5 lines, and every line is written the same way. Well done. You just did what a data collector is paid to do.

Watch out

• Writing things in a different order each time. If one line says "Cash, 4, Pawpaw" and the next says "Banana, Card, 6", nobody can read your table. Keep one order.
• Mixing two things in one box. "4 pawpaws" puts a number and a fruit together. Put "4" under quantity and "Pawpaw" under fruit.
• Thinking data must be numbers. Words like "Cash" and "Pawpaw" are data too.

Say it back

1. In your own words, what is data?
2. Why does Amara write every sale in the same order?
3. Is "Pawpaw" data, even though it is a word?

Show the answers

1. Facts we notice about the world and write down, so we can look at them later.
2. So the facts line up into a table that anyone can read and count.
3. Yes. Data can be words, numbers or dates.

What is next

Amara's notebook now has many lines. But what exactly is one line? It sounds simple, yet getting it wrong breaks every count you make. That is the next lesson.