Stage 3 — Data Exploration
You now have the data. It is probably thousands of rows of numbers, and staring at it tells you nothing at all. This stage turns it into something a human being can actually look at.
1What data exploration is
Tap a stage to stand on it, or press play and watch the work go round. Drag sideways to turn.
It answers: What is this data actually telling us?
2Why a picture wins
Read these six months of sales: 41, 38, 44, 92, 95, 40. You have to think about it. Now draw them as six bars and the answer jumps out before you have finished looking: two months are enormous, the rest are ordinary. Your eyes found that pattern, not your arithmetic.
A list of turns, or a map
3Which picture to use
| Picture | Good for |
|---|---|
| Bar chart | Comparing separate things — sales per month, marks per subject |
| Line chart | Something changing over time — temperature through the year |
| Scatter plot | Whether two things move together — study hours against marks |
| Pie chart | Parts of one whole — how a budget is divided |
| Histogram | How values are spread — how many students scored in each band |
| Map | Anything that has a place — disease cases by district |
4What you are looking for
- Patterns — sales rise every festival season.
- Odd values — one temperature reading of 500°C. Almost certainly a mistake.
- Missing data — a whole column that is empty for half the rows.
- Gaps in coverage — no data at all from one village. That will become bias later.
5From the board papers
▶Show the answer
In the second stage, Data Acquisition, we collect data from reliable and authentic sources. In the third stage, Data Exploration, we represent that data visually — as graphs, charts or maps — so that its patterns can be seen and understood.
6Check yourself
You want to show how the temperature of a city changed across twelve months. Which picture fits best?
What is the main purpose of data exploration?