What is data?
Data is information that we collect to answer a question. "What is the favourite fruit in our class?" "How many days did it rain this month?" To answer, we gather data and then organize it.
Step 1: Ask a good question
A good data question:
- Is clear: everyone understands it.
- Has answers you can count.
- Has a few choices, called categories.
| Unclear question | Better question |
|---|---|
| What do you like? | What is your favourite fruit: apple, banana, grapes or orange? |
| Do you have stuff? | How many pets do you have? |
Step 2: Collect the data
Ways to collect data:
- Survey: ask people and record their answers.
- Observe: watch and count, like how many cars pass by.
- Measure: use tools, like a thermometer each day.
Ask each person only once, and write every answer down right away.
Step 3: Organize the data
Raw answers look messy:
apple, banana, apple, grapes, orange, apple, banana, grapes, apple
Sort them into categories and count:
| Fruit | Votes |
|---|---|
| Apple | 4 |
| Banana | 2 |
| Grapes | 2 |
| Orange | 1 |
Now the data is in a table, and it’s easy to read.
Step 4: Read and answer
From the table:
- Most popular: apple (4 votes)
- Least popular: orange (1 vote)
- Total votes: 4 + 2 + 2 + 1 = 9
Ways to show organized data
Once data is organized, you can show it as a tally chart, a pictograph or a bar graph. Each one makes it easier to compare categories at a glance.
Worked examples
Example 1: Ten children choose a favourite season: 3 summer, 4 winter, 2 fall, 1 spring. Which season won?
Winter, with 4.
Example 2: How many children were asked?
3 + 4 + 2 + 1 = 10.
Example 3: How many more chose winter than spring?
4 − 1 = 3.
Common mistakes
- Asking a question with too many possible answers, so the data is hard to sort.
- Asking the same person twice, which changes the results.
- Forgetting to count every answer before drawing conclusions.
Try it yourself
- Write a survey question about pets.
- Organize this data: red, blue, red, green, blue, red.
- Which colour is most popular?
- How many answers are there in total?
Answers: 1) e.g. Which pet would you most like: dog, cat, fish or bird? 2) red 3, blue 2, green 1 3) red 4) 6
Quick recap
- Data is information collected to answer a question.
- Collect with a survey, by observing or by measuring.
- Organize data into categories in a table to read it easily.