Three columns, three kinds
A shop sheet has three columns: Items in the basket, Waiting time at the till and Customer type.
The items are whole numbers: you cannot have 2.5 items. The waiting time can be 3.4 or 3.43 minutes. The customer type is a label: member, guest or staff. Each column needs different handling.
Key words
| Word | What it means | Example |
|---|---|---|
| Quantitative data | Data that is a number you can count or measure. | 7 items |
| Discrete value | A value you count, with only whole steps between. | 7 items |
| Continuous value | A value you measure, which can be any number in a range. | 3.4 minutes |
| Categorical value | A value that is a label from a fixed list. | member |
| Category | A group that items are put into. | Customer type |
| Transformation | A change from one form of data to another. | Minutes into fast, ok or slow |
| Suitable | Right for the job. | A label suits a pie chart. |
The cells students fill in are left blank in this preview.
By the end of this lesson
Note
I can name a value as counted, measured or a label, and say what suits each.
Starter: what you already know
Have a go
Starter: what you already know
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Three kinds of quantitative value
Values come in three kinds. The first two are numbers, so they are quantitative. The third is a label:
- Discrete values are counted in whole steps: 7 items, 3 tills.
- Continuous values are measured and can be any number in a range: 21.4 degrees, 3.75 seconds.
- Categorical values are labels from a fixed list: member, guest, staff.
Worked example: a shop sheet
| Column | Example | Kind | Why |
|---|---|---|---|
| Items in basket | 7 | Discrete | You count them. There is no 7.5. |
| Waiting time (minutes) | 3.4 | Continuous | You measure it. It can be 3.43. |
| Customer type | member | Categorical | One label from a short list |
| Tills open | 4 | Discrete | You count them. |
| Download speed | 48.2 | Continuous | You measure it. |
The cells students fill in are left blank in this preview.
Check: which kind of value?
Have a go
Check: which kind of value?
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.