Asking Questions and Making Tally Charts
What this lesson covers
- Data is information we collect.
- A variable is the thing we are finding out about, like favourite fruit.
- Some data sorts into groups, called categories.
- We can count each category with a tally chart.
What is data?
- Data is information we collect about the world.
- Ask everyone in your class their favourite fruit. Their answers are data.
- Data can be words, like colours, not just numbers.
Variables and categories
- A variable is the thing we are finding out about.
- Favourite fruit is a variable. Eye colour is a variable.
- Answers like apple, banana or kiwifruit sort into groups. The groups are called categories.
| Variable | Some categories |
|---|---|
| favourite fruit | apple, banana, kiwifruit, orange |
| eye colour | brown, blue, green, hazel |
| how we get to school | walk, car, bus, bike |
Try it: groups or numbers?
Ask a question
- Start with a question: what is the favourite fruit of children in our class?
- Pick a few categories, so the answers are easy to sort.
- Ask each person once.
Tally marks
- Make one mark for each answer: |
- After 4 marks, the 5th mark goes across them: ||||/ is a bundle of 5.
- Count the bundles in 5s, then count on the single marks.
| Tally | Count |
|---|---|
| ||| | 3 |
| ||||/ | 5 |
| ||||/ || | 7 |
| ||||/ ||||/ | 10 |
A tally chart for favourite fruit
- Each child gave one answer.
- Count each category: kiwifruit has the most.
| Fruit | Tally | Count |
|---|---|---|
| apple | ||||/ || | 7 |
| banana | ||| | 3 |
| kiwifruit | ||||/ ||||/ | 10 |
| orange | |||| | 4 |
Try it: turn the tally into a graph
Another question
- Do children in our class have one foot longer than the other?
- Each child stands on paper and a friend checks both feet.
- There are only two categories: yes or no.
| Answer | Tally | Count |
|---|---|---|
| yes | ||||/ | | 6 |
| no | ||||/ ||||/ ||||/ | | 16 |
Common mistakes
- Asking the same person twice.Ask each person once, so every answer counts one time.
- Writing 5 as five straight marks: |||||Draw 4 marks, then put the 5th across them: ||||/. It is quicker to count.
- Using lots of categories for a small class.Keep to a few categories, so each one has enough answers to count.
- Data is only numbers.Data can be words too, like colours or kinds of fruit.
Your turn
1
What number does ||||/ ||| show?
2
What number does ||||/ ||||/ show?
3
How do you show 6 in tally marks?
4
Does favourite colour sort into categories?
5
Look at the fruit tally chart. How many children chose banana?
Show answer
1. 8 2. 10 3. ||||/ | 4. Yes, colours sort into groups 5. 3
What to take away
- Data is information we collect.
- A variable is what we find out about; categories are its groups.
- Tally in bundles of 5, then count.
Report a mistake
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